scsi: zfcp: Trace when request remove fails after qdio send fails

[J-linux.git] / drivers / vfio / pci / vfio_pci_core.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
 *     Author: Alex Williamson <[email protected]>
 *
 * Derived from original vfio:
 * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
 * Author: Tom Lyon, [email protected]
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/aperture.h>
#include <linux/device.h>
#include <linux/eventfd.h>
#include <linux/file.h>
#include <linux/interrupt.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/pci.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/vgaarb.h>
#include <linux/nospec.h>
#include <linux/sched/mm.h>
#if IS_ENABLED(CONFIG_EEH)
#include <asm/eeh.h>
#endif

#include "vfio_pci_priv.h"

#define DRIVER_AUTHOR   "Alex Williamson <[email protected]>"
#define DRIVER_DESC "core driver for VFIO based PCI devices"

static bool nointxmask;
static bool disable_vga;
static bool disable_idle_d3;

/* List of PF's that vfio_pci_core_sriov_configure() has been called on */
static DEFINE_MUTEX(vfio_pci_sriov_pfs_mutex);
static LIST_HEAD(vfio_pci_sriov_pfs);

struct vfio_pci_dummy_resource {
        struct resource         resource;
        int                     index;
        struct list_head        res_next;
};

struct vfio_pci_vf_token {
        struct mutex            lock;
        uuid_t                  uuid;
        int                     users;
};

struct vfio_pci_mmap_vma {
        struct vm_area_struct   *vma;
        struct list_head        vma_next;
};

static inline bool vfio_vga_disabled(void)
{
#ifdef CONFIG_VFIO_PCI_VGA
        return disable_vga;
#else
        return true;
#endif
}

/*
 * Our VGA arbiter participation is limited since we don't know anything
 * about the device itself.  However, if the device is the only VGA device
 * downstream of a bridge and VFIO VGA support is disabled, then we can
 * safely return legacy VGA IO and memory as not decoded since the user
 * has no way to get to it and routing can be disabled externally at the
 * bridge.
 */
static unsigned int vfio_pci_set_decode(struct pci_dev *pdev, bool single_vga)
{
        struct pci_dev *tmp = NULL;
        unsigned char max_busnr;
        unsigned int decodes;

        if (single_vga || !vfio_vga_disabled() || pci_is_root_bus(pdev->bus))
                return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM |
                       VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;

        max_busnr = pci_bus_max_busnr(pdev->bus);
        decodes = VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;

        while ((tmp = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, tmp)) != NULL) {
                if (tmp == pdev ||
                    pci_domain_nr(tmp->bus) != pci_domain_nr(pdev->bus) ||
                    pci_is_root_bus(tmp->bus))
                        continue;

                if (tmp->bus->number >= pdev->bus->number &&
                    tmp->bus->number <= max_busnr) {
                        pci_dev_put(tmp);
                        decodes |= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
                        break;
                }
        }

        return decodes;
}

static void vfio_pci_probe_mmaps(struct vfio_pci_core_device *vdev)
{
        struct resource *res;
        int i;
        struct vfio_pci_dummy_resource *dummy_res;

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                int bar = i + PCI_STD_RESOURCES;

                res = &vdev->pdev->resource[bar];

                if (!IS_ENABLED(CONFIG_VFIO_PCI_MMAP))
                        goto no_mmap;

                if (!(res->flags & IORESOURCE_MEM))
                        goto no_mmap;

                /*
                 * The PCI core shouldn't set up a resource with a
                 * type but zero size. But there may be bugs that
                 * cause us to do that.
                 */
                if (!resource_size(res))
                        goto no_mmap;

                if (resource_size(res) >= PAGE_SIZE) {
                        vdev->bar_mmap_supported[bar] = true;
                        continue;
                }

                if (!(res->start & ~PAGE_MASK)) {
                        /*
                         * Add a dummy resource to reserve the remainder
                         * of the exclusive page in case that hot-add
                         * device's bar is assigned into it.
                         */
                        dummy_res = kzalloc(sizeof(*dummy_res), GFP_KERNEL);
                        if (dummy_res == NULL)
                                goto no_mmap;

                        dummy_res->resource.name = "vfio sub-page reserved";
                        dummy_res->resource.start = res->end + 1;
                        dummy_res->resource.end = res->start + PAGE_SIZE - 1;
                        dummy_res->resource.flags = res->flags;
                        if (request_resource(res->parent,
                                                &dummy_res->resource)) {
                                kfree(dummy_res);
                                goto no_mmap;
                        }
                        dummy_res->index = bar;
                        list_add(&dummy_res->res_next,
                                        &vdev->dummy_resources_list);
                        vdev->bar_mmap_supported[bar] = true;
                        continue;
                }
                /*
                 * Here we don't handle the case when the BAR is not page
                 * aligned because we can't expect the BAR will be
                 * assigned into the same location in a page in guest
                 * when we passthrough the BAR. And it's hard to access
                 * this BAR in userspace because we have no way to get
                 * the BAR's location in a page.
                 */
no_mmap:
                vdev->bar_mmap_supported[bar] = false;
        }
}

struct vfio_pci_group_info;
static void vfio_pci_dev_set_try_reset(struct vfio_device_set *dev_set);
static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
                                      struct vfio_pci_group_info *groups);

/*
 * INTx masking requires the ability to disable INTx signaling via PCI_COMMAND
 * _and_ the ability detect when the device is asserting INTx via PCI_STATUS.
 * If a device implements the former but not the latter we would typically
 * expect broken_intx_masking be set and require an exclusive interrupt.
 * However since we do have control of the device's ability to assert INTx,
 * we can instead pretend that the device does not implement INTx, virtualizing
 * the pin register to report zero and maintaining DisINTx set on the host.
 */
static bool vfio_pci_nointx(struct pci_dev *pdev)
{
        switch (pdev->vendor) {
        case PCI_VENDOR_ID_INTEL:
                switch (pdev->device) {
                /* All i40e (XL710/X710/XXV710) 10/20/25/40GbE NICs */
                case 0x1572:
                case 0x1574:
                case 0x1580 ... 0x1581:
                case 0x1583 ... 0x158b:
                case 0x37d0 ... 0x37d2:
                /* X550 */
                case 0x1563:
                        return true;
                default:
                        return false;
                }
        }

        return false;
}

static void vfio_pci_probe_power_state(struct vfio_pci_core_device *vdev)
{
        struct pci_dev *pdev = vdev->pdev;
        u16 pmcsr;

        if (!pdev->pm_cap)
                return;

        pci_read_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL, &pmcsr);

        vdev->needs_pm_restore = !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET);
}

/*
 * pci_set_power_state() wrapper handling devices which perform a soft reset on
 * D3->D0 transition.  Save state prior to D0/1/2->D3, stash it on the vdev,
 * restore when returned to D0.  Saved separately from pci_saved_state for use
 * by PM capability emulation and separately from pci_dev internal saved state
 * to avoid it being overwritten and consumed around other resets.
 */
int vfio_pci_set_power_state(struct vfio_pci_core_device *vdev, pci_power_t state)
{
        struct pci_dev *pdev = vdev->pdev;
        bool needs_restore = false, needs_save = false;
        int ret;

        /* Prevent changing power state for PFs with VFs enabled */
        if (pci_num_vf(pdev) && state > PCI_D0)
                return -EBUSY;

        if (vdev->needs_pm_restore) {
                if (pdev->current_state < PCI_D3hot && state >= PCI_D3hot) {
                        pci_save_state(pdev);
                        needs_save = true;
                }

                if (pdev->current_state >= PCI_D3hot && state <= PCI_D0)
                        needs_restore = true;
        }

        ret = pci_set_power_state(pdev, state);

        if (!ret) {
                /* D3 might be unsupported via quirk, skip unless in D3 */
                if (needs_save && pdev->current_state >= PCI_D3hot) {
                        /*
                         * The current PCI state will be saved locally in
                         * 'pm_save' during the D3hot transition. When the
                         * device state is changed to D0 again with the current
                         * function, then pci_store_saved_state() will restore
                         * the state and will free the memory pointed by
                         * 'pm_save'. There are few cases where the PCI power
                         * state can be changed to D0 without the involvement
                         * of the driver. For these cases, free the earlier
                         * allocated memory first before overwriting 'pm_save'
                         * to prevent the memory leak.
                         */
                        kfree(vdev->pm_save);
                        vdev->pm_save = pci_store_saved_state(pdev);
                } else if (needs_restore) {
                        pci_load_and_free_saved_state(pdev, &vdev->pm_save);
                        pci_restore_state(pdev);
                }
        }

        return ret;
}

static int vfio_pci_runtime_pm_entry(struct vfio_pci_core_device *vdev,
                                     struct eventfd_ctx *efdctx)
{
        /*
         * The vdev power related flags are protected with 'memory_lock'
         * semaphore.
         */
        vfio_pci_zap_and_down_write_memory_lock(vdev);
        if (vdev->pm_runtime_engaged) {
                up_write(&vdev->memory_lock);
                return -EINVAL;
        }

        vdev->pm_runtime_engaged = true;
        vdev->pm_wake_eventfd_ctx = efdctx;
        pm_runtime_put_noidle(&vdev->pdev->dev);
        up_write(&vdev->memory_lock);

        return 0;
}

static int vfio_pci_core_pm_entry(struct vfio_device *device, u32 flags,
                                  void __user *arg, size_t argsz)
{
        struct vfio_pci_core_device *vdev =
                container_of(device, struct vfio_pci_core_device, vdev);
        int ret;

        ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, 0);
        if (ret != 1)
                return ret;

        /*
         * Inside vfio_pci_runtime_pm_entry(), only the runtime PM usage count
         * will be decremented. The pm_runtime_put() will be invoked again
         * while returning from the ioctl and then the device can go into
         * runtime suspended state.
         */
        return vfio_pci_runtime_pm_entry(vdev, NULL);
}

static int vfio_pci_core_pm_entry_with_wakeup(
        struct vfio_device *device, u32 flags,
        struct vfio_device_low_power_entry_with_wakeup __user *arg,
        size_t argsz)
{
        struct vfio_pci_core_device *vdev =
                container_of(device, struct vfio_pci_core_device, vdev);
        struct vfio_device_low_power_entry_with_wakeup entry;
        struct eventfd_ctx *efdctx;
        int ret;

        ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET,
                                 sizeof(entry));
        if (ret != 1)
                return ret;

        if (copy_from_user(&entry, arg, sizeof(entry)))
                return -EFAULT;

        if (entry.wakeup_eventfd < 0)
                return -EINVAL;

        efdctx = eventfd_ctx_fdget(entry.wakeup_eventfd);
        if (IS_ERR(efdctx))
                return PTR_ERR(efdctx);

        ret = vfio_pci_runtime_pm_entry(vdev, efdctx);
        if (ret)
                eventfd_ctx_put(efdctx);

        return ret;
}

static void __vfio_pci_runtime_pm_exit(struct vfio_pci_core_device *vdev)
{
        if (vdev->pm_runtime_engaged) {
                vdev->pm_runtime_engaged = false;
                pm_runtime_get_noresume(&vdev->pdev->dev);

                if (vdev->pm_wake_eventfd_ctx) {
                        eventfd_ctx_put(vdev->pm_wake_eventfd_ctx);
                        vdev->pm_wake_eventfd_ctx = NULL;
                }
        }
}

static void vfio_pci_runtime_pm_exit(struct vfio_pci_core_device *vdev)
{
        /*
         * The vdev power related flags are protected with 'memory_lock'
         * semaphore.
         */
        down_write(&vdev->memory_lock);
        __vfio_pci_runtime_pm_exit(vdev);
        up_write(&vdev->memory_lock);
}

static int vfio_pci_core_pm_exit(struct vfio_device *device, u32 flags,
                                 void __user *arg, size_t argsz)
{
        struct vfio_pci_core_device *vdev =
                container_of(device, struct vfio_pci_core_device, vdev);
        int ret;

        ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, 0);
        if (ret != 1)
                return ret;

        /*
         * The device is always in the active state here due to pm wrappers
         * around ioctls. If the device had entered a low power state and
         * pm_wake_eventfd_ctx is valid, vfio_pci_core_runtime_resume() has
         * already signaled the eventfd and exited low power mode itself.
         * pm_runtime_engaged protects the redundant call here.
         */
        vfio_pci_runtime_pm_exit(vdev);
        return 0;
}

#ifdef CONFIG_PM
static int vfio_pci_core_runtime_suspend(struct device *dev)
{
        struct vfio_pci_core_device *vdev = dev_get_drvdata(dev);

        down_write(&vdev->memory_lock);
        /*
         * The user can move the device into D3hot state before invoking
         * power management IOCTL. Move the device into D0 state here and then
         * the pci-driver core runtime PM suspend function will move the device
         * into the low power state. Also, for the devices which have
         * NoSoftRst-, it will help in restoring the original state
         * (saved locally in 'vdev->pm_save').
         */
        vfio_pci_set_power_state(vdev, PCI_D0);
        up_write(&vdev->memory_lock);

        /*
         * If INTx is enabled, then mask INTx before going into the runtime
         * suspended state and unmask the same in the runtime resume.
         * If INTx has already been masked by the user, then
         * vfio_pci_intx_mask() will return false and in that case, INTx
         * should not be unmasked in the runtime resume.
         */
        vdev->pm_intx_masked = ((vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX) &&
                                vfio_pci_intx_mask(vdev));

        return 0;
}

static int vfio_pci_core_runtime_resume(struct device *dev)
{
        struct vfio_pci_core_device *vdev = dev_get_drvdata(dev);

        /*
         * Resume with a pm_wake_eventfd_ctx signals the eventfd and exit
         * low power mode.
         */
        down_write(&vdev->memory_lock);
        if (vdev->pm_wake_eventfd_ctx) {
                eventfd_signal(vdev->pm_wake_eventfd_ctx, 1);
                __vfio_pci_runtime_pm_exit(vdev);
        }
        up_write(&vdev->memory_lock);

        if (vdev->pm_intx_masked)
                vfio_pci_intx_unmask(vdev);

        return 0;
}
#endif /* CONFIG_PM */

/*
 * The pci-driver core runtime PM routines always save the device state
 * before going into suspended state. If the device is going into low power
 * state with only with runtime PM ops, then no explicit handling is needed
 * for the devices which have NoSoftRst-.
 */
static const struct dev_pm_ops vfio_pci_core_pm_ops = {
        SET_RUNTIME_PM_OPS(vfio_pci_core_runtime_suspend,
                           vfio_pci_core_runtime_resume,
                           NULL)
};

int vfio_pci_core_enable(struct vfio_pci_core_device *vdev)
{
        struct pci_dev *pdev = vdev->pdev;
        int ret;
        u16 cmd;
        u8 msix_pos;

        if (!disable_idle_d3) {
                ret = pm_runtime_resume_and_get(&pdev->dev);
                if (ret < 0)
                        return ret;
        }

        /* Don't allow our initial saved state to include busmaster */
        pci_clear_master(pdev);

        ret = pci_enable_device(pdev);
        if (ret)
                goto out_power;

        /* If reset fails because of the device lock, fail this path entirely */
        ret = pci_try_reset_function(pdev);
        if (ret == -EAGAIN)
                goto out_disable_device;

        vdev->reset_works = !ret;
        pci_save_state(pdev);
        vdev->pci_saved_state = pci_store_saved_state(pdev);
        if (!vdev->pci_saved_state)
                pci_dbg(pdev, "%s: Couldn't store saved state\n", __func__);

        if (likely(!nointxmask)) {
                if (vfio_pci_nointx(pdev)) {
                        pci_info(pdev, "Masking broken INTx support\n");
                        vdev->nointx = true;
                        pci_intx(pdev, 0);
                } else
                        vdev->pci_2_3 = pci_intx_mask_supported(pdev);
        }

        pci_read_config_word(pdev, PCI_COMMAND, &cmd);
        if (vdev->pci_2_3 && (cmd & PCI_COMMAND_INTX_DISABLE)) {
                cmd &= ~PCI_COMMAND_INTX_DISABLE;
                pci_write_config_word(pdev, PCI_COMMAND, cmd);
        }

        ret = vfio_pci_zdev_open_device(vdev);
        if (ret)
                goto out_free_state;

        ret = vfio_config_init(vdev);
        if (ret)
                goto out_free_zdev;

        msix_pos = pdev->msix_cap;
        if (msix_pos) {
                u16 flags;
                u32 table;

                pci_read_config_word(pdev, msix_pos + PCI_MSIX_FLAGS, &flags);
                pci_read_config_dword(pdev, msix_pos + PCI_MSIX_TABLE, &table);

                vdev->msix_bar = table & PCI_MSIX_TABLE_BIR;
                vdev->msix_offset = table & PCI_MSIX_TABLE_OFFSET;
                vdev->msix_size = ((flags & PCI_MSIX_FLAGS_QSIZE) + 1) * 16;
        } else
                vdev->msix_bar = 0xFF;

        if (!vfio_vga_disabled() && vfio_pci_is_vga(pdev))
                vdev->has_vga = true;


        return 0;

out_free_zdev:
        vfio_pci_zdev_close_device(vdev);
out_free_state:
        kfree(vdev->pci_saved_state);
        vdev->pci_saved_state = NULL;
out_disable_device:
        pci_disable_device(pdev);
out_power:
        if (!disable_idle_d3)
                pm_runtime_put(&pdev->dev);
        return ret;
}
EXPORT_SYMBOL_GPL(vfio_pci_core_enable);

void vfio_pci_core_disable(struct vfio_pci_core_device *vdev)
{
        struct pci_dev *pdev = vdev->pdev;
        struct vfio_pci_dummy_resource *dummy_res, *tmp;
        struct vfio_pci_ioeventfd *ioeventfd, *ioeventfd_tmp;
        int i, bar;

        /* For needs_reset */
        lockdep_assert_held(&vdev->vdev.dev_set->lock);

        /*
         * This function can be invoked while the power state is non-D0.
         * This non-D0 power state can be with or without runtime PM.
         * vfio_pci_runtime_pm_exit() will internally increment the usage
         * count corresponding to pm_runtime_put() called during low power
         * feature entry and then pm_runtime_resume() will wake up the device,
         * if the device has already gone into the suspended state. Otherwise,
         * the vfio_pci_set_power_state() will change the device power state
         * to D0.
         */
        vfio_pci_runtime_pm_exit(vdev);
        pm_runtime_resume(&pdev->dev);

        /*
         * This function calls __pci_reset_function_locked() which internally
         * can use pci_pm_reset() for the function reset. pci_pm_reset() will
         * fail if the power state is non-D0. Also, for the devices which
         * have NoSoftRst-, the reset function can cause the PCI config space
         * reset without restoring the original state (saved locally in
         * 'vdev->pm_save').
         */
        vfio_pci_set_power_state(vdev, PCI_D0);

        /* Stop the device from further DMA */
        pci_clear_master(pdev);

        vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
                                VFIO_IRQ_SET_ACTION_TRIGGER,
                                vdev->irq_type, 0, 0, NULL);

        /* Device closed, don't need mutex here */
        list_for_each_entry_safe(ioeventfd, ioeventfd_tmp,
                                 &vdev->ioeventfds_list, next) {
                vfio_virqfd_disable(&ioeventfd->virqfd);
                list_del(&ioeventfd->next);
                kfree(ioeventfd);
        }
        vdev->ioeventfds_nr = 0;

        vdev->virq_disabled = false;

        for (i = 0; i < vdev->num_regions; i++)
                vdev->region[i].ops->release(vdev, &vdev->region[i]);

        vdev->num_regions = 0;
        kfree(vdev->region);
        vdev->region = NULL; /* don't krealloc a freed pointer */

        vfio_config_free(vdev);

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                bar = i + PCI_STD_RESOURCES;
                if (!vdev->barmap[bar])
                        continue;
                pci_iounmap(pdev, vdev->barmap[bar]);
                pci_release_selected_regions(pdev, 1 << bar);
                vdev->barmap[bar] = NULL;
        }

        list_for_each_entry_safe(dummy_res, tmp,
                                 &vdev->dummy_resources_list, res_next) {
                list_del(&dummy_res->res_next);
                release_resource(&dummy_res->resource);
                kfree(dummy_res);
        }

        vdev->needs_reset = true;

        vfio_pci_zdev_close_device(vdev);

        /*
         * If we have saved state, restore it.  If we can reset the device,
         * even better.  Resetting with current state seems better than
         * nothing, but saving and restoring current state without reset
         * is just busy work.
         */
        if (pci_load_and_free_saved_state(pdev, &vdev->pci_saved_state)) {
                pci_info(pdev, "%s: Couldn't reload saved state\n", __func__);

                if (!vdev->reset_works)
                        goto out;

                pci_save_state(pdev);
        }

        /*
         * Disable INTx and MSI, presumably to avoid spurious interrupts
         * during reset.  Stolen from pci_reset_function()
         */
        pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);

        /*
         * Try to get the locks ourselves to prevent a deadlock. The
         * success of this is dependent on being able to lock the device,
         * which is not always possible.
         * We can not use the "try" reset interface here, which will
         * overwrite the previously restored configuration information.
         */
        if (vdev->reset_works && pci_dev_trylock(pdev)) {
                if (!__pci_reset_function_locked(pdev))
                        vdev->needs_reset = false;
                pci_dev_unlock(pdev);
        }

        pci_restore_state(pdev);
out:
        pci_disable_device(pdev);

        vfio_pci_dev_set_try_reset(vdev->vdev.dev_set);

        /* Put the pm-runtime usage counter acquired during enable */
        if (!disable_idle_d3)
                pm_runtime_put(&pdev->dev);
}
EXPORT_SYMBOL_GPL(vfio_pci_core_disable);

void vfio_pci_core_close_device(struct vfio_device *core_vdev)
{
        struct vfio_pci_core_device *vdev =
                container_of(core_vdev, struct vfio_pci_core_device, vdev);

        if (vdev->sriov_pf_core_dev) {
                mutex_lock(&vdev->sriov_pf_core_dev->vf_token->lock);
                WARN_ON(!vdev->sriov_pf_core_dev->vf_token->users);
                vdev->sriov_pf_core_dev->vf_token->users--;
                mutex_unlock(&vdev->sriov_pf_core_dev->vf_token->lock);
        }
#if IS_ENABLED(CONFIG_EEH)
        eeh_dev_release(vdev->pdev);
#endif
        vfio_pci_core_disable(vdev);

        mutex_lock(&vdev->igate);
        if (vdev->err_trigger) {
                eventfd_ctx_put(vdev->err_trigger);
                vdev->err_trigger = NULL;
        }
        if (vdev->req_trigger) {
                eventfd_ctx_put(vdev->req_trigger);
                vdev->req_trigger = NULL;
        }
        mutex_unlock(&vdev->igate);
}
EXPORT_SYMBOL_GPL(vfio_pci_core_close_device);

void vfio_pci_core_finish_enable(struct vfio_pci_core_device *vdev)
{
        vfio_pci_probe_mmaps(vdev);
#if IS_ENABLED(CONFIG_EEH)
        eeh_dev_open(vdev->pdev);
#endif

        if (vdev->sriov_pf_core_dev) {
                mutex_lock(&vdev->sriov_pf_core_dev->vf_token->lock);
                vdev->sriov_pf_core_dev->vf_token->users++;
                mutex_unlock(&vdev->sriov_pf_core_dev->vf_token->lock);
        }
}
EXPORT_SYMBOL_GPL(vfio_pci_core_finish_enable);

static int vfio_pci_get_irq_count(struct vfio_pci_core_device *vdev, int irq_type)
{
        if (irq_type == VFIO_PCI_INTX_IRQ_INDEX) {
                u8 pin;

                if (!IS_ENABLED(CONFIG_VFIO_PCI_INTX) ||
                    vdev->nointx || vdev->pdev->is_virtfn)
                        return 0;

                pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, &pin);

                return pin ? 1 : 0;
        } else if (irq_type == VFIO_PCI_MSI_IRQ_INDEX) {
                u8 pos;
                u16 flags;

                pos = vdev->pdev->msi_cap;
                if (pos) {
                        pci_read_config_word(vdev->pdev,
                                             pos + PCI_MSI_FLAGS, &flags);
                        return 1 << ((flags & PCI_MSI_FLAGS_QMASK) >> 1);
                }
        } else if (irq_type == VFIO_PCI_MSIX_IRQ_INDEX) {
                u8 pos;
                u16 flags;

                pos = vdev->pdev->msix_cap;
                if (pos) {
                        pci_read_config_word(vdev->pdev,
                                             pos + PCI_MSIX_FLAGS, &flags);

                        return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
                }
        } else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX) {
                if (pci_is_pcie(vdev->pdev))
                        return 1;
        } else if (irq_type == VFIO_PCI_REQ_IRQ_INDEX) {
                return 1;
        }

        return 0;
}

static int vfio_pci_count_devs(struct pci_dev *pdev, void *data)
{
        (*(int *)data)++;
        return 0;
}

struct vfio_pci_fill_info {
        int max;
        int cur;
        struct vfio_pci_dependent_device *devices;
};

static int vfio_pci_fill_devs(struct pci_dev *pdev, void *data)
{
        struct vfio_pci_fill_info *fill = data;
        struct iommu_group *iommu_group;

        if (fill->cur == fill->max)
                return -EAGAIN; /* Something changed, try again */

        iommu_group = iommu_group_get(&pdev->dev);
        if (!iommu_group)
                return -EPERM; /* Cannot reset non-isolated devices */

        fill->devices[fill->cur].group_id = iommu_group_id(iommu_group);
        fill->devices[fill->cur].segment = pci_domain_nr(pdev->bus);
        fill->devices[fill->cur].bus = pdev->bus->number;
        fill->devices[fill->cur].devfn = pdev->devfn;
        fill->cur++;
        iommu_group_put(iommu_group);
        return 0;
}

struct vfio_pci_group_info {
        int count;
        struct file **files;
};

static bool vfio_pci_dev_below_slot(struct pci_dev *pdev, struct pci_slot *slot)
{
        for (; pdev; pdev = pdev->bus->self)
                if (pdev->bus == slot->bus)
                        return (pdev->slot == slot);
        return false;
}

struct vfio_pci_walk_info {
        int (*fn)(struct pci_dev *pdev, void *data);
        void *data;
        struct pci_dev *pdev;
        bool slot;
        int ret;
};

static int vfio_pci_walk_wrapper(struct pci_dev *pdev, void *data)
{
        struct vfio_pci_walk_info *walk = data;

        if (!walk->slot || vfio_pci_dev_below_slot(pdev, walk->pdev->slot))
                walk->ret = walk->fn(pdev, walk->data);

        return walk->ret;
}

static int vfio_pci_for_each_slot_or_bus(struct pci_dev *pdev,
                                         int (*fn)(struct pci_dev *,
                                                   void *data), void *data,
                                         bool slot)
{
        struct vfio_pci_walk_info walk = {
                .fn = fn, .data = data, .pdev = pdev, .slot = slot, .ret = 0,
        };

        pci_walk_bus(pdev->bus, vfio_pci_walk_wrapper, &walk);

        return walk.ret;
}

static int msix_mmappable_cap(struct vfio_pci_core_device *vdev,
                              struct vfio_info_cap *caps)
{
        struct vfio_info_cap_header header = {
                .id = VFIO_REGION_INFO_CAP_MSIX_MAPPABLE,
                .version = 1
        };

        return vfio_info_add_capability(caps, &header, sizeof(header));
}

int vfio_pci_core_register_dev_region(struct vfio_pci_core_device *vdev,
                                      unsigned int type, unsigned int subtype,
                                      const struct vfio_pci_regops *ops,
                                      size_t size, u32 flags, void *data)
{
        struct vfio_pci_region *region;

        region = krealloc(vdev->region,
                          (vdev->num_regions + 1) * sizeof(*region),
                          GFP_KERNEL);
        if (!region)
                return -ENOMEM;

        vdev->region = region;
        vdev->region[vdev->num_regions].type = type;
        vdev->region[vdev->num_regions].subtype = subtype;
        vdev->region[vdev->num_regions].ops = ops;
        vdev->region[vdev->num_regions].size = size;
        vdev->region[vdev->num_regions].flags = flags;
        vdev->region[vdev->num_regions].data = data;

        vdev->num_regions++;

        return 0;
}
EXPORT_SYMBOL_GPL(vfio_pci_core_register_dev_region);

static int vfio_pci_ioctl_get_info(struct vfio_pci_core_device *vdev,
                                   struct vfio_device_info __user *arg)
{
        unsigned long minsz = offsetofend(struct vfio_device_info, num_irqs);
        struct vfio_device_info info;
        struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
        unsigned long capsz;
        int ret;

        /* For backward compatibility, cannot require this */
        capsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);

        if (copy_from_user(&info, arg, minsz))
                return -EFAULT;

        if (info.argsz < minsz)
                return -EINVAL;

        if (info.argsz >= capsz) {
                minsz = capsz;
                info.cap_offset = 0;
        }

        info.flags = VFIO_DEVICE_FLAGS_PCI;

        if (vdev->reset_works)
                info.flags |= VFIO_DEVICE_FLAGS_RESET;

        info.num_regions = VFIO_PCI_NUM_REGIONS + vdev->num_regions;
        info.num_irqs = VFIO_PCI_NUM_IRQS;

        ret = vfio_pci_info_zdev_add_caps(vdev, &caps);
        if (ret && ret != -ENODEV) {
                pci_warn(vdev->pdev,
                         "Failed to setup zPCI info capabilities\n");
                return ret;
        }

        if (caps.size) {
                info.flags |= VFIO_DEVICE_FLAGS_CAPS;
                if (info.argsz < sizeof(info) + caps.size) {
                        info.argsz = sizeof(info) + caps.size;
                } else {
                        vfio_info_cap_shift(&caps, sizeof(info));
                        if (copy_to_user(arg + 1, caps.buf, caps.size)) {
                                kfree(caps.buf);
                                return -EFAULT;
                        }
                        info.cap_offset = sizeof(*arg);
                }

                kfree(caps.buf);
        }

        return copy_to_user(arg, &info, minsz) ? -EFAULT : 0;
}

static int vfio_pci_ioctl_get_region_info(struct vfio_pci_core_device *vdev,
                                          struct vfio_region_info __user *arg)
{
        unsigned long minsz = offsetofend(struct vfio_region_info, offset);
        struct pci_dev *pdev = vdev->pdev;
        struct vfio_region_info info;
        struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
        int i, ret;

        if (copy_from_user(&info, arg, minsz))
                return -EFAULT;

        if (info.argsz < minsz)
                return -EINVAL;

        switch (info.index) {
        case VFIO_PCI_CONFIG_REGION_INDEX:
                info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
                info.size = pdev->cfg_size;
                info.flags = VFIO_REGION_INFO_FLAG_READ |
                             VFIO_REGION_INFO_FLAG_WRITE;
                break;
        case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
                info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
                info.size = pci_resource_len(pdev, info.index);
                if (!info.size) {
                        info.flags = 0;
                        break;
                }

                info.flags = VFIO_REGION_INFO_FLAG_READ |
                             VFIO_REGION_INFO_FLAG_WRITE;
                if (vdev->bar_mmap_supported[info.index]) {
                        info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
                        if (info.index == vdev->msix_bar) {
                                ret = msix_mmappable_cap(vdev, &caps);
                                if (ret)
                                        return ret;
                        }
                }

                break;
        case VFIO_PCI_ROM_REGION_INDEX: {
                void __iomem *io;
                size_t size;
                u16 cmd;

                info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
                info.flags = 0;

                /* Report the BAR size, not the ROM size */
                info.size = pci_resource_len(pdev, info.index);
                if (!info.size) {
                        /* Shadow ROMs appear as PCI option ROMs */
                        if (pdev->resource[PCI_ROM_RESOURCE].flags &
                            IORESOURCE_ROM_SHADOW)
                                info.size = 0x20000;
                        else
                                break;
                }

                /*
                 * Is it really there?  Enable memory decode for implicit access
                 * in pci_map_rom().
                 */
                cmd = vfio_pci_memory_lock_and_enable(vdev);
                io = pci_map_rom(pdev, &size);
                if (io) {
                        info.flags = VFIO_REGION_INFO_FLAG_READ;
                        pci_unmap_rom(pdev, io);
                } else {
                        info.size = 0;
                }
                vfio_pci_memory_unlock_and_restore(vdev, cmd);

                break;
        }
        case VFIO_PCI_VGA_REGION_INDEX:
                if (!vdev->has_vga)
                        return -EINVAL;

                info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
                info.size = 0xc0000;
                info.flags = VFIO_REGION_INFO_FLAG_READ |
                             VFIO_REGION_INFO_FLAG_WRITE;

                break;
        default: {
                struct vfio_region_info_cap_type cap_type = {
                        .header.id = VFIO_REGION_INFO_CAP_TYPE,
                        .header.version = 1
                };

                if (info.index >= VFIO_PCI_NUM_REGIONS + vdev->num_regions)
                        return -EINVAL;
                info.index = array_index_nospec(
                        info.index, VFIO_PCI_NUM_REGIONS + vdev->num_regions);

                i = info.index - VFIO_PCI_NUM_REGIONS;

                info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
                info.size = vdev->region[i].size;
                info.flags = vdev->region[i].flags;

                cap_type.type = vdev->region[i].type;
                cap_type.subtype = vdev->region[i].subtype;

                ret = vfio_info_add_capability(&caps, &cap_type.header,
                                               sizeof(cap_type));
                if (ret)
                        return ret;

                if (vdev->region[i].ops->add_capability) {
                        ret = vdev->region[i].ops->add_capability(
                                vdev, &vdev->region[i], &caps);
                        if (ret)
                                return ret;
                }
        }
        }

        if (caps.size) {
                info.flags |= VFIO_REGION_INFO_FLAG_CAPS;
                if (info.argsz < sizeof(info) + caps.size) {
                        info.argsz = sizeof(info) + caps.size;
                        info.cap_offset = 0;
                } else {
                        vfio_info_cap_shift(&caps, sizeof(info));
                        if (copy_to_user(arg + 1, caps.buf, caps.size)) {
                                kfree(caps.buf);
                                return -EFAULT;
                        }
                        info.cap_offset = sizeof(*arg);
                }

                kfree(caps.buf);
        }

        return copy_to_user(arg, &info, minsz) ? -EFAULT : 0;
}

static int vfio_pci_ioctl_get_irq_info(struct vfio_pci_core_device *vdev,
                                       struct vfio_irq_info __user *arg)
{
        unsigned long minsz = offsetofend(struct vfio_irq_info, count);
        struct vfio_irq_info info;

        if (copy_from_user(&info, arg, minsz))
                return -EFAULT;

        if (info.argsz < minsz || info.index >= VFIO_PCI_NUM_IRQS)
                return -EINVAL;

        switch (info.index) {
        case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
        case VFIO_PCI_REQ_IRQ_INDEX:
                break;
        case VFIO_PCI_ERR_IRQ_INDEX:
                if (pci_is_pcie(vdev->pdev))
                        break;
                fallthrough;
        default:
                return -EINVAL;
        }

        info.flags = VFIO_IRQ_INFO_EVENTFD;

        info.count = vfio_pci_get_irq_count(vdev, info.index);

        if (info.index == VFIO_PCI_INTX_IRQ_INDEX)
                info.flags |=
                        (VFIO_IRQ_INFO_MASKABLE | VFIO_IRQ_INFO_AUTOMASKED);
        else
                info.flags |= VFIO_IRQ_INFO_NORESIZE;

        return copy_to_user(arg, &info, minsz) ? -EFAULT : 0;
}

static int vfio_pci_ioctl_set_irqs(struct vfio_pci_core_device *vdev,
                                   struct vfio_irq_set __user *arg)
{
        unsigned long minsz = offsetofend(struct vfio_irq_set, count);
        struct vfio_irq_set hdr;
        u8 *data = NULL;
        int max, ret = 0;
        size_t data_size = 0;

        if (copy_from_user(&hdr, arg, minsz))
                return -EFAULT;

        max = vfio_pci_get_irq_count(vdev, hdr.index);

        ret = vfio_set_irqs_validate_and_prepare(&hdr, max, VFIO_PCI_NUM_IRQS,
                                                 &data_size);
        if (ret)
                return ret;

        if (data_size) {
                data = memdup_user(&arg->data, data_size);
                if (IS_ERR(data))
                        return PTR_ERR(data);
        }

        mutex_lock(&vdev->igate);

        ret = vfio_pci_set_irqs_ioctl(vdev, hdr.flags, hdr.index, hdr.start,
                                      hdr.count, data);

        mutex_unlock(&vdev->igate);
        kfree(data);

        return ret;
}

static int vfio_pci_ioctl_reset(struct vfio_pci_core_device *vdev,
                                void __user *arg)
{
        int ret;

        if (!vdev->reset_works)
                return -EINVAL;

        vfio_pci_zap_and_down_write_memory_lock(vdev);

        /*
         * This function can be invoked while the power state is non-D0. If
         * pci_try_reset_function() has been called while the power state is
         * non-D0, then pci_try_reset_function() will internally set the power
         * state to D0 without vfio driver involvement. For the devices which
         * have NoSoftRst-, the reset function can cause the PCI config space
         * reset without restoring the original state (saved locally in
         * 'vdev->pm_save').
         */
        vfio_pci_set_power_state(vdev, PCI_D0);

        ret = pci_try_reset_function(vdev->pdev);
        up_write(&vdev->memory_lock);

        return ret;
}

static int vfio_pci_ioctl_get_pci_hot_reset_info(
        struct vfio_pci_core_device *vdev,
        struct vfio_pci_hot_reset_info __user *arg)
{
        unsigned long minsz =
                offsetofend(struct vfio_pci_hot_reset_info, count);
        struct vfio_pci_hot_reset_info hdr;
        struct vfio_pci_fill_info fill = { 0 };
        struct vfio_pci_dependent_device *devices = NULL;
        bool slot = false;
        int ret = 0;

        if (copy_from_user(&hdr, arg, minsz))
                return -EFAULT;

        if (hdr.argsz < minsz)
                return -EINVAL;

        hdr.flags = 0;

        /* Can we do a slot or bus reset or neither? */
        if (!pci_probe_reset_slot(vdev->pdev->slot))
                slot = true;
        else if (pci_probe_reset_bus(vdev->pdev->bus))
                return -ENODEV;

        /* How many devices are affected? */
        ret = vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_count_devs,
                                            &fill.max, slot);
        if (ret)
                return ret;

        WARN_ON(!fill.max); /* Should always be at least one */

        /*
         * If there's enough space, fill it now, otherwise return -ENOSPC and
         * the number of devices affected.
         */
        if (hdr.argsz < sizeof(hdr) + (fill.max * sizeof(*devices))) {
                ret = -ENOSPC;
                hdr.count = fill.max;
                goto reset_info_exit;
        }

        devices = kcalloc(fill.max, sizeof(*devices), GFP_KERNEL);
        if (!devices)
                return -ENOMEM;

        fill.devices = devices;

        ret = vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_fill_devs,
                                            &fill, slot);

        /*
         * If a device was removed between counting and filling, we may come up
         * short of fill.max.  If a device was added, we'll have a return of
         * -EAGAIN above.
         */
        if (!ret)
                hdr.count = fill.cur;

reset_info_exit:
        if (copy_to_user(arg, &hdr, minsz))
                ret = -EFAULT;

        if (!ret) {
                if (copy_to_user(&arg->devices, devices,
                                 hdr.count * sizeof(*devices)))
                        ret = -EFAULT;
        }

        kfree(devices);
        return ret;
}

static int vfio_pci_ioctl_pci_hot_reset(struct vfio_pci_core_device *vdev,
                                        struct vfio_pci_hot_reset __user *arg)
{
        unsigned long minsz = offsetofend(struct vfio_pci_hot_reset, count);
        struct vfio_pci_hot_reset hdr;
        int32_t *group_fds;
        struct file **files;
        struct vfio_pci_group_info info;
        bool slot = false;
        int file_idx, count = 0, ret = 0;

        if (copy_from_user(&hdr, arg, minsz))
                return -EFAULT;

        if (hdr.argsz < minsz || hdr.flags)
                return -EINVAL;

        /* Can we do a slot or bus reset or neither? */
        if (!pci_probe_reset_slot(vdev->pdev->slot))
                slot = true;
        else if (pci_probe_reset_bus(vdev->pdev->bus))
                return -ENODEV;

        /*
         * We can't let userspace give us an arbitrarily large buffer to copy,
         * so verify how many we think there could be.  Note groups can have
         * multiple devices so one group per device is the max.
         */
        ret = vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_count_devs,
                                            &count, slot);
        if (ret)
                return ret;

        /* Somewhere between 1 and count is OK */
        if (!hdr.count || hdr.count > count)
                return -EINVAL;

        group_fds = kcalloc(hdr.count, sizeof(*group_fds), GFP_KERNEL);
        files = kcalloc(hdr.count, sizeof(*files), GFP_KERNEL);
        if (!group_fds || !files) {
                kfree(group_fds);
                kfree(files);
                return -ENOMEM;
        }

        if (copy_from_user(group_fds, arg->group_fds,
                           hdr.count * sizeof(*group_fds))) {
                kfree(group_fds);
                kfree(files);
                return -EFAULT;
        }

        /*
         * For each group_fd, get the group through the vfio external user
         * interface and store the group and iommu ID.  This ensures the group
         * is held across the reset.
         */
        for (file_idx = 0; file_idx < hdr.count; file_idx++) {
                struct file *file = fget(group_fds[file_idx]);

                if (!file) {
                        ret = -EBADF;
                        break;
                }

                /* Ensure the FD is a vfio group FD.*/
                if (!vfio_file_is_group(file)) {
                        fput(file);
                        ret = -EINVAL;
                        break;
                }

                files[file_idx] = file;
        }

        kfree(group_fds);

        /* release reference to groups on error */
        if (ret)
                goto hot_reset_release;

        info.count = hdr.count;
        info.files = files;

        ret = vfio_pci_dev_set_hot_reset(vdev->vdev.dev_set, &info);

hot_reset_release:
        for (file_idx--; file_idx >= 0; file_idx--)
                fput(files[file_idx]);

        kfree(files);
        return ret;
}

static int vfio_pci_ioctl_ioeventfd(struct vfio_pci_core_device *vdev,
                                    struct vfio_device_ioeventfd __user *arg)
{
        unsigned long minsz = offsetofend(struct vfio_device_ioeventfd, fd);
        struct vfio_device_ioeventfd ioeventfd;
        int count;

        if (copy_from_user(&ioeventfd, arg, minsz))
                return -EFAULT;

        if (ioeventfd.argsz < minsz)
                return -EINVAL;

        if (ioeventfd.flags & ~VFIO_DEVICE_IOEVENTFD_SIZE_MASK)
                return -EINVAL;

        count = ioeventfd.flags & VFIO_DEVICE_IOEVENTFD_SIZE_MASK;

        if (hweight8(count) != 1 || ioeventfd.fd < -1)
                return -EINVAL;

        return vfio_pci_ioeventfd(vdev, ioeventfd.offset, ioeventfd.data, count,
                                  ioeventfd.fd);
}

long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
                         unsigned long arg)
{
        struct vfio_pci_core_device *vdev =
                container_of(core_vdev, struct vfio_pci_core_device, vdev);
        void __user *uarg = (void __user *)arg;

        switch (cmd) {
        case VFIO_DEVICE_GET_INFO:
                return vfio_pci_ioctl_get_info(vdev, uarg);
        case VFIO_DEVICE_GET_IRQ_INFO:
                return vfio_pci_ioctl_get_irq_info(vdev, uarg);
        case VFIO_DEVICE_GET_PCI_HOT_RESET_INFO:
                return vfio_pci_ioctl_get_pci_hot_reset_info(vdev, uarg);
        case VFIO_DEVICE_GET_REGION_INFO:
                return vfio_pci_ioctl_get_region_info(vdev, uarg);
        case VFIO_DEVICE_IOEVENTFD:
                return vfio_pci_ioctl_ioeventfd(vdev, uarg);
        case VFIO_DEVICE_PCI_HOT_RESET:
                return vfio_pci_ioctl_pci_hot_reset(vdev, uarg);
        case VFIO_DEVICE_RESET:
                return vfio_pci_ioctl_reset(vdev, uarg);
        case VFIO_DEVICE_SET_IRQS:
                return vfio_pci_ioctl_set_irqs(vdev, uarg);
        default:
                return -ENOTTY;
        }
}
EXPORT_SYMBOL_GPL(vfio_pci_core_ioctl);

static int vfio_pci_core_feature_token(struct vfio_device *device, u32 flags,
                                       uuid_t __user *arg, size_t argsz)
{
        struct vfio_pci_core_device *vdev =
                container_of(device, struct vfio_pci_core_device, vdev);
        uuid_t uuid;
        int ret;

        if (!vdev->vf_token)
                return -ENOTTY;
        /*
         * We do not support GET of the VF Token UUID as this could
         * expose the token of the previous device user.
         */
        ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET,
                                 sizeof(uuid));
        if (ret != 1)
                return ret;

        if (copy_from_user(&uuid, arg, sizeof(uuid)))
                return -EFAULT;

        mutex_lock(&vdev->vf_token->lock);
        uuid_copy(&vdev->vf_token->uuid, &uuid);
        mutex_unlock(&vdev->vf_token->lock);
        return 0;
}

int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags,
                                void __user *arg, size_t argsz)
{
        switch (flags & VFIO_DEVICE_FEATURE_MASK) {
        case VFIO_DEVICE_FEATURE_LOW_POWER_ENTRY:
                return vfio_pci_core_pm_entry(device, flags, arg, argsz);
        case VFIO_DEVICE_FEATURE_LOW_POWER_ENTRY_WITH_WAKEUP:
                return vfio_pci_core_pm_entry_with_wakeup(device, flags,
                                                          arg, argsz);
        case VFIO_DEVICE_FEATURE_LOW_POWER_EXIT:
                return vfio_pci_core_pm_exit(device, flags, arg, argsz);
        case VFIO_DEVICE_FEATURE_PCI_VF_TOKEN:
                return vfio_pci_core_feature_token(device, flags, arg, argsz);
        default:
                return -ENOTTY;
        }
}
EXPORT_SYMBOL_GPL(vfio_pci_core_ioctl_feature);

static ssize_t vfio_pci_rw(struct vfio_pci_core_device *vdev, char __user *buf,
                           size_t count, loff_t *ppos, bool iswrite)
{
        unsigned int index = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
        int ret;

        if (index >= VFIO_PCI_NUM_REGIONS + vdev->num_regions)
                return -EINVAL;

        ret = pm_runtime_resume_and_get(&vdev->pdev->dev);
        if (ret) {
                pci_info_ratelimited(vdev->pdev, "runtime resume failed %d\n",
                                     ret);
                return -EIO;
        }

        switch (index) {
        case VFIO_PCI_CONFIG_REGION_INDEX:
                ret = vfio_pci_config_rw(vdev, buf, count, ppos, iswrite);
                break;

        case VFIO_PCI_ROM_REGION_INDEX:
                if (iswrite)
                        ret = -EINVAL;
                else
                        ret = vfio_pci_bar_rw(vdev, buf, count, ppos, false);
                break;

        case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
                ret = vfio_pci_bar_rw(vdev, buf, count, ppos, iswrite);
                break;

        case VFIO_PCI_VGA_REGION_INDEX:
                ret = vfio_pci_vga_rw(vdev, buf, count, ppos, iswrite);
                break;

        default:
                index -= VFIO_PCI_NUM_REGIONS;
                ret = vdev->region[index].ops->rw(vdev, buf,
                                                   count, ppos, iswrite);
                break;
        }

        pm_runtime_put(&vdev->pdev->dev);
        return ret;
}

ssize_t vfio_pci_core_read(struct vfio_device *core_vdev, char __user *buf,
                size_t count, loff_t *ppos)
{
        struct vfio_pci_core_device *vdev =
                container_of(core_vdev, struct vfio_pci_core_device, vdev);

        if (!count)
                return 0;

        return vfio_pci_rw(vdev, buf, count, ppos, false);
}
EXPORT_SYMBOL_GPL(vfio_pci_core_read);

ssize_t vfio_pci_core_write(struct vfio_device *core_vdev, const char __user *buf,
                size_t count, loff_t *ppos)
{
        struct vfio_pci_core_device *vdev =
                container_of(core_vdev, struct vfio_pci_core_device, vdev);

        if (!count)
                return 0;

        return vfio_pci_rw(vdev, (char __user *)buf, count, ppos, true);
}
EXPORT_SYMBOL_GPL(vfio_pci_core_write);

/* Return 1 on zap and vma_lock acquired, 0 on contention (only with @try) */
static int vfio_pci_zap_and_vma_lock(struct vfio_pci_core_device *vdev, bool try)
{
        struct vfio_pci_mmap_vma *mmap_vma, *tmp;

        /*
         * Lock ordering:
         * vma_lock is nested under mmap_lock for vm_ops callback paths.
         * The memory_lock semaphore is used by both code paths calling
         * into this function to zap vmas and the vm_ops.fault callback
         * to protect the memory enable state of the device.
         *
         * When zapping vmas we need to maintain the mmap_lock => vma_lock
         * ordering, which requires using vma_lock to walk vma_list to
         * acquire an mm, then dropping vma_lock to get the mmap_lock and
         * reacquiring vma_lock.  This logic is derived from similar
         * requirements in uverbs_user_mmap_disassociate().
         *
         * mmap_lock must always be the top-level lock when it is taken.
         * Therefore we can only hold the memory_lock write lock when
         * vma_list is empty, as we'd need to take mmap_lock to clear
         * entries.  vma_list can only be guaranteed empty when holding
         * vma_lock, thus memory_lock is nested under vma_lock.
         *
         * This enables the vm_ops.fault callback to acquire vma_lock,
         * followed by memory_lock read lock, while already holding
         * mmap_lock without risk of deadlock.
         */
        while (1) {
                struct mm_struct *mm = NULL;

                if (try) {
                        if (!mutex_trylock(&vdev->vma_lock))
                                return 0;
                } else {
                        mutex_lock(&vdev->vma_lock);
                }
                while (!list_empty(&vdev->vma_list)) {
                        mmap_vma = list_first_entry(&vdev->vma_list,
                                                    struct vfio_pci_mmap_vma,
                                                    vma_next);
                        mm = mmap_vma->vma->vm_mm;
                        if (mmget_not_zero(mm))
                                break;

                        list_del(&mmap_vma->vma_next);
                        kfree(mmap_vma);
                        mm = NULL;
                }
                if (!mm)
                        return 1;
                mutex_unlock(&vdev->vma_lock);

                if (try) {
                        if (!mmap_read_trylock(mm)) {
                                mmput(mm);
                                return 0;
                        }
                } else {
                        mmap_read_lock(mm);
                }
                if (try) {
                        if (!mutex_trylock(&vdev->vma_lock)) {
                                mmap_read_unlock(mm);
                                mmput(mm);
                                return 0;
                        }
                } else {
                        mutex_lock(&vdev->vma_lock);
                }
                list_for_each_entry_safe(mmap_vma, tmp,
                                         &vdev->vma_list, vma_next) {
                        struct vm_area_struct *vma = mmap_vma->vma;

                        if (vma->vm_mm != mm)
                                continue;

                        list_del(&mmap_vma->vma_next);
                        kfree(mmap_vma);

                        zap_vma_ptes(vma, vma->vm_start,
                                     vma->vm_end - vma->vm_start);
                }
                mutex_unlock(&vdev->vma_lock);
                mmap_read_unlock(mm);
                mmput(mm);
        }
}

void vfio_pci_zap_and_down_write_memory_lock(struct vfio_pci_core_device *vdev)
{
        vfio_pci_zap_and_vma_lock(vdev, false);
        down_write(&vdev->memory_lock);
        mutex_unlock(&vdev->vma_lock);
}

u16 vfio_pci_memory_lock_and_enable(struct vfio_pci_core_device *vdev)
{
        u16 cmd;

        down_write(&vdev->memory_lock);
        pci_read_config_word(vdev->pdev, PCI_COMMAND, &cmd);
        if (!(cmd & PCI_COMMAND_MEMORY))
                pci_write_config_word(vdev->pdev, PCI_COMMAND,
                                      cmd | PCI_COMMAND_MEMORY);

        return cmd;
}

void vfio_pci_memory_unlock_and_restore(struct vfio_pci_core_device *vdev, u16 cmd)
{
        pci_write_config_word(vdev->pdev, PCI_COMMAND, cmd);
        up_write(&vdev->memory_lock);
}

/* Caller holds vma_lock */
static int __vfio_pci_add_vma(struct vfio_pci_core_device *vdev,
                              struct vm_area_struct *vma)
{
        struct vfio_pci_mmap_vma *mmap_vma;

        mmap_vma = kmalloc(sizeof(*mmap_vma), GFP_KERNEL);
        if (!mmap_vma)
                return -ENOMEM;

        mmap_vma->vma = vma;
        list_add(&mmap_vma->vma_next, &vdev->vma_list);

        return 0;
}

/*
 * Zap mmaps on open so that we can fault them in on access and therefore
 * our vma_list only tracks mappings accessed since last zap.
 */
static void vfio_pci_mmap_open(struct vm_area_struct *vma)
{
        zap_vma_ptes(vma, vma->vm_start, vma->vm_end - vma->vm_start);
}

static void vfio_pci_mmap_close(struct vm_area_struct *vma)
{
        struct vfio_pci_core_device *vdev = vma->vm_private_data;
        struct vfio_pci_mmap_vma *mmap_vma;

        mutex_lock(&vdev->vma_lock);
        list_for_each_entry(mmap_vma, &vdev->vma_list, vma_next) {
                if (mmap_vma->vma == vma) {
                        list_del(&mmap_vma->vma_next);
                        kfree(mmap_vma);
                        break;
                }
        }
        mutex_unlock(&vdev->vma_lock);
}

static vm_fault_t vfio_pci_mmap_fault(struct vm_fault *vmf)
{
        struct vm_area_struct *vma = vmf->vma;
        struct vfio_pci_core_device *vdev = vma->vm_private_data;
        struct vfio_pci_mmap_vma *mmap_vma;
        vm_fault_t ret = VM_FAULT_NOPAGE;

        mutex_lock(&vdev->vma_lock);
        down_read(&vdev->memory_lock);

        /*
         * Memory region cannot be accessed if the low power feature is engaged
         * or memory access is disabled.
         */
        if (vdev->pm_runtime_engaged || !__vfio_pci_memory_enabled(vdev)) {
                ret = VM_FAULT_SIGBUS;
                goto up_out;
        }

        /*
         * We populate the whole vma on fault, so we need to test whether
         * the vma has already been mapped, such as for concurrent faults
         * to the same vma.  io_remap_pfn_range() will trigger a BUG_ON if
         * we ask it to fill the same range again.
         */
        list_for_each_entry(mmap_vma, &vdev->vma_list, vma_next) {
                if (mmap_vma->vma == vma)
                        goto up_out;
        }

        if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
                               vma->vm_end - vma->vm_start,
                               vma->vm_page_prot)) {
                ret = VM_FAULT_SIGBUS;
                zap_vma_ptes(vma, vma->vm_start, vma->vm_end - vma->vm_start);
                goto up_out;
        }

        if (__vfio_pci_add_vma(vdev, vma)) {
                ret = VM_FAULT_OOM;
                zap_vma_ptes(vma, vma->vm_start, vma->vm_end - vma->vm_start);
        }

up_out:
        up_read(&vdev->memory_lock);
        mutex_unlock(&vdev->vma_lock);
        return ret;
}

static const struct vm_operations_struct vfio_pci_mmap_ops = {
        .open = vfio_pci_mmap_open,
        .close = vfio_pci_mmap_close,
        .fault = vfio_pci_mmap_fault,
};

int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma)
{
        struct vfio_pci_core_device *vdev =
                container_of(core_vdev, struct vfio_pci_core_device, vdev);
        struct pci_dev *pdev = vdev->pdev;
        unsigned int index;
        u64 phys_len, req_len, pgoff, req_start;
        int ret;

        index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT);

        if (index >= VFIO_PCI_NUM_REGIONS + vdev->num_regions)
                return -EINVAL;
        if (vma->vm_end < vma->vm_start)
                return -EINVAL;
        if ((vma->vm_flags & VM_SHARED) == 0)
                return -EINVAL;
        if (index >= VFIO_PCI_NUM_REGIONS) {
                int regnum = index - VFIO_PCI_NUM_REGIONS;
                struct vfio_pci_region *region = vdev->region + regnum;

                if (region->ops && region->ops->mmap &&
                    (region->flags & VFIO_REGION_INFO_FLAG_MMAP))
                        return region->ops->mmap(vdev, region, vma);
                return -EINVAL;
        }
        if (index >= VFIO_PCI_ROM_REGION_INDEX)
                return -EINVAL;
        if (!vdev->bar_mmap_supported[index])
                return -EINVAL;

        phys_len = PAGE_ALIGN(pci_resource_len(pdev, index));
        req_len = vma->vm_end - vma->vm_start;
        pgoff = vma->vm_pgoff &
                ((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
        req_start = pgoff << PAGE_SHIFT;

        if (req_start + req_len > phys_len)
                return -EINVAL;

        /*
         * Even though we don't make use of the barmap for the mmap,
         * we need to request the region and the barmap tracks that.
         */
        if (!vdev->barmap[index]) {
                ret = pci_request_selected_regions(pdev,
                                                   1 << index, "vfio-pci");
                if (ret)
                        return ret;

                vdev->barmap[index] = pci_iomap(pdev, index, 0);
                if (!vdev->barmap[index]) {
                        pci_release_selected_regions(pdev, 1 << index);
                        return -ENOMEM;
                }
        }

        vma->vm_private_data = vdev;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
        vma->vm_pgoff = (pci_resource_start(pdev, index) >> PAGE_SHIFT) + pgoff;

        /*
         * See remap_pfn_range(), called from vfio_pci_fault() but we can't
         * change vm_flags within the fault handler.  Set them now.
         */
        vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
        vma->vm_ops = &vfio_pci_mmap_ops;

        return 0;
}
EXPORT_SYMBOL_GPL(vfio_pci_core_mmap);

void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count)
{
        struct vfio_pci_core_device *vdev =
                container_of(core_vdev, struct vfio_pci_core_device, vdev);
        struct pci_dev *pdev = vdev->pdev;

        mutex_lock(&vdev->igate);

        if (vdev->req_trigger) {
                if (!(count % 10))
                        pci_notice_ratelimited(pdev,
                                "Relaying device request to user (#%u)\n",
                                count);
                eventfd_signal(vdev->req_trigger, 1);
        } else if (count == 0) {
                pci_warn(pdev,
                        "No device request channel registered, blocked until released by user\n");
        }

        mutex_unlock(&vdev->igate);
}
EXPORT_SYMBOL_GPL(vfio_pci_core_request);

static int vfio_pci_validate_vf_token(struct vfio_pci_core_device *vdev,
                                      bool vf_token, uuid_t *uuid)
{
        /*
         * There's always some degree of trust or collaboration between SR-IOV
         * PF and VFs, even if just that the PF hosts the SR-IOV capability and
         * can disrupt VFs with a reset, but often the PF has more explicit
         * access to deny service to the VF or access data passed through the
         * VF.  We therefore require an opt-in via a shared VF token (UUID) to
         * represent this trust.  This both prevents that a VF driver might
         * assume the PF driver is a trusted, in-kernel driver, and also that
         * a PF driver might be replaced with a rogue driver, unknown to in-use
         * VF drivers.
         *
         * Therefore when presented with a VF, if the PF is a vfio device and
         * it is bound to the vfio-pci driver, the user needs to provide a VF
         * token to access the device, in the form of appending a vf_token to
         * the device name, for example:
         *
         * "0000:04:10.0 vf_token=bd8d9d2b-5a5f-4f5a-a211-f591514ba1f3"
         *
         * When presented with a PF which has VFs in use, the user must also
         * provide the current VF token to prove collaboration with existing
         * VF users.  If VFs are not in use, the VF token provided for the PF
         * device will act to set the VF token.
         *
         * If the VF token is provided but unused, an error is generated.
         */
        if (vdev->pdev->is_virtfn) {
                struct vfio_pci_core_device *pf_vdev = vdev->sriov_pf_core_dev;
                bool match;

                if (!pf_vdev) {
                        if (!vf_token)
                                return 0; /* PF is not vfio-pci, no VF token */

                        pci_info_ratelimited(vdev->pdev,
                                "VF token incorrectly provided, PF not bound to vfio-pci\n");
                        return -EINVAL;
                }

                if (!vf_token) {
                        pci_info_ratelimited(vdev->pdev,
                                "VF token required to access device\n");
                        return -EACCES;
                }

                mutex_lock(&pf_vdev->vf_token->lock);
                match = uuid_equal(uuid, &pf_vdev->vf_token->uuid);
                mutex_unlock(&pf_vdev->vf_token->lock);

                if (!match) {
                        pci_info_ratelimited(vdev->pdev,
                                "Incorrect VF token provided for device\n");
                        return -EACCES;
                }
        } else if (vdev->vf_token) {
                mutex_lock(&vdev->vf_token->lock);
                if (vdev->vf_token->users) {
                        if (!vf_token) {
                                mutex_unlock(&vdev->vf_token->lock);
                                pci_info_ratelimited(vdev->pdev,
                                        "VF token required to access device\n");
                                return -EACCES;
                        }

                        if (!uuid_equal(uuid, &vdev->vf_token->uuid)) {
                                mutex_unlock(&vdev->vf_token->lock);
                                pci_info_ratelimited(vdev->pdev,
                                        "Incorrect VF token provided for device\n");
                                return -EACCES;
                        }
                } else if (vf_token) {
                        uuid_copy(&vdev->vf_token->uuid, uuid);
                }

                mutex_unlock(&vdev->vf_token->lock);
        } else if (vf_token) {
                pci_info_ratelimited(vdev->pdev,
                        "VF token incorrectly provided, not a PF or VF\n");
                return -EINVAL;
        }

        return 0;
}

#define VF_TOKEN_ARG "vf_token="

int vfio_pci_core_match(struct vfio_device *core_vdev, char *buf)
{
        struct vfio_pci_core_device *vdev =
                container_of(core_vdev, struct vfio_pci_core_device, vdev);
        bool vf_token = false;
        uuid_t uuid;
        int ret;

        if (strncmp(pci_name(vdev->pdev), buf, strlen(pci_name(vdev->pdev))))
                return 0; /* No match */

        if (strlen(buf) > strlen(pci_name(vdev->pdev))) {
                buf += strlen(pci_name(vdev->pdev));

                if (*buf != ' ')
                        return 0; /* No match: non-whitespace after name */

                while (*buf) {
                        if (*buf == ' ') {
                                buf++;
                                continue;
                        }

                        if (!vf_token && !strncmp(buf, VF_TOKEN_ARG,
                                                  strlen(VF_TOKEN_ARG))) {
                                buf += strlen(VF_TOKEN_ARG);

                                if (strlen(buf) < UUID_STRING_LEN)
                                        return -EINVAL;

                                ret = uuid_parse(buf, &uuid);
                                if (ret)
                                        return ret;

                                vf_token = true;
                                buf += UUID_STRING_LEN;
                        } else {
                                /* Unknown/duplicate option */
                                return -EINVAL;
                        }
                }
        }

        ret = vfio_pci_validate_vf_token(vdev, vf_token, &uuid);
        if (ret)
                return ret;

        return 1; /* Match */
}
EXPORT_SYMBOL_GPL(vfio_pci_core_match);

static int vfio_pci_bus_notifier(struct notifier_block *nb,
                                 unsigned long action, void *data)
{
        struct vfio_pci_core_device *vdev = container_of(nb,
                                                    struct vfio_pci_core_device, nb);
        struct device *dev = data;
        struct pci_dev *pdev = to_pci_dev(dev);
        struct pci_dev *physfn = pci_physfn(pdev);

        if (action == BUS_NOTIFY_ADD_DEVICE &&
            pdev->is_virtfn && physfn == vdev->pdev) {
                pci_info(vdev->pdev, "Captured SR-IOV VF %s driver_override\n",
                         pci_name(pdev));
                pdev->driver_override = kasprintf(GFP_KERNEL, "%s",
                                                  vdev->vdev.ops->name);
        } else if (action == BUS_NOTIFY_BOUND_DRIVER &&
                   pdev->is_virtfn && physfn == vdev->pdev) {
                struct pci_driver *drv = pci_dev_driver(pdev);

                if (drv && drv != pci_dev_driver(vdev->pdev))
                        pci_warn(vdev->pdev,
                                 "VF %s bound to driver %s while PF bound to driver %s\n",
                                 pci_name(pdev), drv->name,
                                 pci_dev_driver(vdev->pdev)->name);
        }

        return 0;
}

static int vfio_pci_vf_init(struct vfio_pci_core_device *vdev)
{
        struct pci_dev *pdev = vdev->pdev;
        struct vfio_pci_core_device *cur;
        struct pci_dev *physfn;
        int ret;

        if (pdev->is_virtfn) {
                /*
                 * If this VF was created by our vfio_pci_core_sriov_configure()
                 * then we can find the PF vfio_pci_core_device now, and due to
                 * the locking in pci_disable_sriov() it cannot change until
                 * this VF device driver is removed.
                 */
                physfn = pci_physfn(vdev->pdev);
                mutex_lock(&vfio_pci_sriov_pfs_mutex);
                list_for_each_entry(cur, &vfio_pci_sriov_pfs, sriov_pfs_item) {
                        if (cur->pdev == physfn) {
                                vdev->sriov_pf_core_dev = cur;
                                break;
                        }
                }
                mutex_unlock(&vfio_pci_sriov_pfs_mutex);
                return 0;
        }

        /* Not a SRIOV PF */
        if (!pdev->is_physfn)
                return 0;

        vdev->vf_token = kzalloc(sizeof(*vdev->vf_token), GFP_KERNEL);
        if (!vdev->vf_token)
                return -ENOMEM;

        mutex_init(&vdev->vf_token->lock);
        uuid_gen(&vdev->vf_token->uuid);

        vdev->nb.notifier_call = vfio_pci_bus_notifier;
        ret = bus_register_notifier(&pci_bus_type, &vdev->nb);
        if (ret) {
                kfree(vdev->vf_token);
                return ret;
        }
        return 0;
}

static void vfio_pci_vf_uninit(struct vfio_pci_core_device *vdev)
{
        if (!vdev->vf_token)
                return;

        bus_unregister_notifier(&pci_bus_type, &vdev->nb);
        WARN_ON(vdev->vf_token->users);
        mutex_destroy(&vdev->vf_token->lock);
        kfree(vdev->vf_token);
}

static int vfio_pci_vga_init(struct vfio_pci_core_device *vdev)
{
        struct pci_dev *pdev = vdev->pdev;
        int ret;

        if (!vfio_pci_is_vga(pdev))
                return 0;

        ret = aperture_remove_conflicting_pci_devices(pdev, vdev->vdev.ops->name);
        if (ret)
                return ret;

        ret = vga_client_register(pdev, vfio_pci_set_decode);
        if (ret)
                return ret;
        vga_set_legacy_decoding(pdev, vfio_pci_set_decode(pdev, false));
        return 0;
}

static void vfio_pci_vga_uninit(struct vfio_pci_core_device *vdev)
{
        struct pci_dev *pdev = vdev->pdev;

        if (!vfio_pci_is_vga(pdev))
                return;
        vga_client_unregister(pdev);
        vga_set_legacy_decoding(pdev, VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM |
                                              VGA_RSRC_LEGACY_IO |
                                              VGA_RSRC_LEGACY_MEM);
}

int vfio_pci_core_init_dev(struct vfio_device *core_vdev)
{
        struct vfio_pci_core_device *vdev =
                container_of(core_vdev, struct vfio_pci_core_device, vdev);

        vdev->pdev = to_pci_dev(core_vdev->dev);
        vdev->irq_type = VFIO_PCI_NUM_IRQS;
        mutex_init(&vdev->igate);
        spin_lock_init(&vdev->irqlock);
        mutex_init(&vdev->ioeventfds_lock);
        INIT_LIST_HEAD(&vdev->dummy_resources_list);
        INIT_LIST_HEAD(&vdev->ioeventfds_list);
        mutex_init(&vdev->vma_lock);
        INIT_LIST_HEAD(&vdev->vma_list);
        INIT_LIST_HEAD(&vdev->sriov_pfs_item);
        init_rwsem(&vdev->memory_lock);

        return 0;
}
EXPORT_SYMBOL_GPL(vfio_pci_core_init_dev);

void vfio_pci_core_release_dev(struct vfio_device *core_vdev)
{
        struct vfio_pci_core_device *vdev =
                container_of(core_vdev, struct vfio_pci_core_device, vdev);

        mutex_destroy(&vdev->igate);
        mutex_destroy(&vdev->ioeventfds_lock);
        mutex_destroy(&vdev->vma_lock);
        kfree(vdev->region);
        kfree(vdev->pm_save);
}
EXPORT_SYMBOL_GPL(vfio_pci_core_release_dev);

int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev)
{
        struct pci_dev *pdev = vdev->pdev;
        struct device *dev = &pdev->dev;
        int ret;

        /* Drivers must set the vfio_pci_core_device to their drvdata */
        if (WARN_ON(vdev != dev_get_drvdata(dev)))
                return -EINVAL;

        if (pdev->hdr_type != PCI_HEADER_TYPE_NORMAL)
                return -EINVAL;

        if (vdev->vdev.mig_ops) {
                if (!(vdev->vdev.mig_ops->migration_get_state &&
                      vdev->vdev.mig_ops->migration_set_state &&
                      vdev->vdev.mig_ops->migration_get_data_size) ||
                    !(vdev->vdev.migration_flags & VFIO_MIGRATION_STOP_COPY))
                        return -EINVAL;
        }

        if (vdev->vdev.log_ops && !(vdev->vdev.log_ops->log_start &&
            vdev->vdev.log_ops->log_stop &&
            vdev->vdev.log_ops->log_read_and_clear))
                return -EINVAL;

        /*
         * Prevent binding to PFs with VFs enabled, the VFs might be in use
         * by the host or other users.  We cannot capture the VFs if they
         * already exist, nor can we track VF users.  Disabling SR-IOV here
         * would initiate removing the VFs, which would unbind the driver,
         * which is prone to blocking if that VF is also in use by vfio-pci.
         * Just reject these PFs and let the user sort it out.
         */
        if (pci_num_vf(pdev)) {
                pci_warn(pdev, "Cannot bind to PF with SR-IOV enabled\n");
                return -EBUSY;
        }

        if (pci_is_root_bus(pdev->bus)) {
                ret = vfio_assign_device_set(&vdev->vdev, vdev);
        } else if (!pci_probe_reset_slot(pdev->slot)) {
                ret = vfio_assign_device_set(&vdev->vdev, pdev->slot);
        } else {
                /*
                 * If there is no slot reset support for this device, the whole
                 * bus needs to be grouped together to support bus-wide resets.
                 */
                ret = vfio_assign_device_set(&vdev->vdev, pdev->bus);
        }

        if (ret)
                return ret;
        ret = vfio_pci_vf_init(vdev);
        if (ret)
                return ret;
        ret = vfio_pci_vga_init(vdev);
        if (ret)
                goto out_vf;

        vfio_pci_probe_power_state(vdev);

        /*
         * pci-core sets the device power state to an unknown value at
         * bootup and after being removed from a driver.  The only
         * transition it allows from this unknown state is to D0, which
         * typically happens when a driver calls pci_enable_device().
         * We're not ready to enable the device yet, but we do want to
         * be able to get to D3.  Therefore first do a D0 transition
         * before enabling runtime PM.
         */
        vfio_pci_set_power_state(vdev, PCI_D0);

        dev->driver->pm = &vfio_pci_core_pm_ops;
        pm_runtime_allow(dev);
        if (!disable_idle_d3)
                pm_runtime_put(dev);

        ret = vfio_register_group_dev(&vdev->vdev);
        if (ret)
                goto out_power;
        return 0;

out_power:
        if (!disable_idle_d3)
                pm_runtime_get_noresume(dev);

        pm_runtime_forbid(dev);
out_vf:
        vfio_pci_vf_uninit(vdev);
        return ret;
}
EXPORT_SYMBOL_GPL(vfio_pci_core_register_device);

void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev)
{
        vfio_pci_core_sriov_configure(vdev, 0);

        vfio_unregister_group_dev(&vdev->vdev);

        vfio_pci_vf_uninit(vdev);
        vfio_pci_vga_uninit(vdev);

        if (!disable_idle_d3)
                pm_runtime_get_noresume(&vdev->pdev->dev);

        pm_runtime_forbid(&vdev->pdev->dev);
}
EXPORT_SYMBOL_GPL(vfio_pci_core_unregister_device);

pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
                                                pci_channel_state_t state)
{
        struct vfio_pci_core_device *vdev = dev_get_drvdata(&pdev->dev);

        mutex_lock(&vdev->igate);

        if (vdev->err_trigger)
                eventfd_signal(vdev->err_trigger, 1);

        mutex_unlock(&vdev->igate);

        return PCI_ERS_RESULT_CAN_RECOVER;
}
EXPORT_SYMBOL_GPL(vfio_pci_core_aer_err_detected);

int vfio_pci_core_sriov_configure(struct vfio_pci_core_device *vdev,
                                  int nr_virtfn)
{
        struct pci_dev *pdev = vdev->pdev;
        int ret = 0;

        device_lock_assert(&pdev->dev);

        if (nr_virtfn) {
                mutex_lock(&vfio_pci_sriov_pfs_mutex);
                /*
                 * The thread that adds the vdev to the list is the only thread
                 * that gets to call pci_enable_sriov() and we will only allow
                 * it to be called once without going through
                 * pci_disable_sriov()
                 */
                if (!list_empty(&vdev->sriov_pfs_item)) {
                        ret = -EINVAL;
                        goto out_unlock;
                }
                list_add_tail(&vdev->sriov_pfs_item, &vfio_pci_sriov_pfs);
                mutex_unlock(&vfio_pci_sriov_pfs_mutex);

                /*
                 * The PF power state should always be higher than the VF power
                 * state. The PF can be in low power state either with runtime
                 * power management (when there is no user) or PCI_PM_CTRL
                 * register write by the user. If PF is in the low power state,
                 * then change the power state to D0 first before enabling
                 * SR-IOV. Also, this function can be called at any time, and
                 * userspace PCI_PM_CTRL write can race against this code path,
                 * so protect the same with 'memory_lock'.
                 */
                ret = pm_runtime_resume_and_get(&pdev->dev);
                if (ret)
                        goto out_del;

                down_write(&vdev->memory_lock);
                vfio_pci_set_power_state(vdev, PCI_D0);
                ret = pci_enable_sriov(pdev, nr_virtfn);
                up_write(&vdev->memory_lock);
                if (ret) {
                        pm_runtime_put(&pdev->dev);
                        goto out_del;
                }
                return nr_virtfn;
        }

        if (pci_num_vf(pdev)) {
                pci_disable_sriov(pdev);
                pm_runtime_put(&pdev->dev);
        }

out_del:
        mutex_lock(&vfio_pci_sriov_pfs_mutex);
        list_del_init(&vdev->sriov_pfs_item);
out_unlock:
        mutex_unlock(&vfio_pci_sriov_pfs_mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(vfio_pci_core_sriov_configure);

const struct pci_error_handlers vfio_pci_core_err_handlers = {
        .error_detected = vfio_pci_core_aer_err_detected,
};
EXPORT_SYMBOL_GPL(vfio_pci_core_err_handlers);

static bool vfio_dev_in_groups(struct vfio_pci_core_device *vdev,
                               struct vfio_pci_group_info *groups)
{
        unsigned int i;

        for (i = 0; i < groups->count; i++)
                if (vfio_file_has_dev(groups->files[i], &vdev->vdev))
                        return true;
        return false;
}

static int vfio_pci_is_device_in_set(struct pci_dev *pdev, void *data)
{
        struct vfio_device_set *dev_set = data;
        struct vfio_device *cur;

        list_for_each_entry(cur, &dev_set->device_list, dev_set_list)
                if (cur->dev == &pdev->dev)
                        return 0;
        return -EBUSY;
}

/*
 * vfio-core considers a group to be viable and will create a vfio_device even
 * if some devices are bound to drivers like pci-stub or pcieport. Here we
 * require all PCI devices to be inside our dev_set since that ensures they stay
 * put and that every driver controlling the device can co-ordinate with the
 * device reset.
 *
 * Returns the pci_dev to pass to pci_reset_bus() if every PCI device to be
 * reset is inside the dev_set, and pci_reset_bus() can succeed. NULL otherwise.
 */
static struct pci_dev *
vfio_pci_dev_set_resettable(struct vfio_device_set *dev_set)
{
        struct pci_dev *pdev;

        lockdep_assert_held(&dev_set->lock);

        /*
         * By definition all PCI devices in the dev_set share the same PCI
         * reset, so any pci_dev will have the same outcomes for
         * pci_probe_reset_*() and pci_reset_bus().
         */
        pdev = list_first_entry(&dev_set->device_list,
                                struct vfio_pci_core_device,
                                vdev.dev_set_list)->pdev;

        /* pci_reset_bus() is supported */
        if (pci_probe_reset_slot(pdev->slot) && pci_probe_reset_bus(pdev->bus))
                return NULL;

        if (vfio_pci_for_each_slot_or_bus(pdev, vfio_pci_is_device_in_set,
                                          dev_set,
                                          !pci_probe_reset_slot(pdev->slot)))
                return NULL;
        return pdev;
}

static int vfio_pci_dev_set_pm_runtime_get(struct vfio_device_set *dev_set)
{
        struct vfio_pci_core_device *cur;
        int ret;

        list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list) {
                ret = pm_runtime_resume_and_get(&cur->pdev->dev);
                if (ret)
                        goto unwind;
        }

        return 0;

unwind:
        list_for_each_entry_continue_reverse(cur, &dev_set->device_list,
                                             vdev.dev_set_list)
                pm_runtime_put(&cur->pdev->dev);

        return ret;
}

/*
 * We need to get memory_lock for each device, but devices can share mmap_lock,
 * therefore we need to zap and hold the vma_lock for each device, and only then
 * get each memory_lock.
 */
static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
                                      struct vfio_pci_group_info *groups)
{
        struct vfio_pci_core_device *cur_mem;
        struct vfio_pci_core_device *cur_vma;
        struct vfio_pci_core_device *cur;
        struct pci_dev *pdev;
        bool is_mem = true;
        int ret;

        mutex_lock(&dev_set->lock);
        cur_mem = list_first_entry(&dev_set->device_list,
                                   struct vfio_pci_core_device,
                                   vdev.dev_set_list);

        pdev = vfio_pci_dev_set_resettable(dev_set);
        if (!pdev) {
                ret = -EINVAL;
                goto err_unlock;
        }

        /*
         * Some of the devices in the dev_set can be in the runtime suspended
         * state. Increment the usage count for all the devices in the dev_set
         * before reset and decrement the same after reset.
         */
        ret = vfio_pci_dev_set_pm_runtime_get(dev_set);
        if (ret)
                goto err_unlock;

        list_for_each_entry(cur_vma, &dev_set->device_list, vdev.dev_set_list) {
                /*
                 * Test whether all the affected devices are contained by the
                 * set of groups provided by the user.
                 */
                if (!vfio_dev_in_groups(cur_vma, groups)) {
                        ret = -EINVAL;
                        goto err_undo;
                }

                /*
                 * Locking multiple devices is prone to deadlock, runaway and
                 * unwind if we hit contention.
                 */
                if (!vfio_pci_zap_and_vma_lock(cur_vma, true)) {
                        ret = -EBUSY;
                        goto err_undo;
                }
        }
        cur_vma = NULL;

        list_for_each_entry(cur_mem, &dev_set->device_list, vdev.dev_set_list) {
                if (!down_write_trylock(&cur_mem->memory_lock)) {
                        ret = -EBUSY;
                        goto err_undo;
                }
                mutex_unlock(&cur_mem->vma_lock);
        }
        cur_mem = NULL;

        /*
         * The pci_reset_bus() will reset all the devices in the bus.
         * The power state can be non-D0 for some of the devices in the bus.
         * For these devices, the pci_reset_bus() will internally set
         * the power state to D0 without vfio driver involvement.
         * For the devices which have NoSoftRst-, the reset function can
         * cause the PCI config space reset without restoring the original
         * state (saved locally in 'vdev->pm_save').
         */
        list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list)
                vfio_pci_set_power_state(cur, PCI_D0);

        ret = pci_reset_bus(pdev);

err_undo:
        list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list) {
                if (cur == cur_mem)
                        is_mem = false;
                if (cur == cur_vma)
                        break;
                if (is_mem)
                        up_write(&cur->memory_lock);
                else
                        mutex_unlock(&cur->vma_lock);
        }

        list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list)
                pm_runtime_put(&cur->pdev->dev);
err_unlock:
        mutex_unlock(&dev_set->lock);
        return ret;
}

static bool vfio_pci_dev_set_needs_reset(struct vfio_device_set *dev_set)
{
        struct vfio_pci_core_device *cur;
        bool needs_reset = false;

        /* No other VFIO device in the set can be open. */
        if (vfio_device_set_open_count(dev_set) > 1)
                return false;

        list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list)
                needs_reset |= cur->needs_reset;
        return needs_reset;
}

/*
 * If a bus or slot reset is available for the provided dev_set and:
 *  - All of the devices affected by that bus or slot reset are unused
 *  - At least one of the affected devices is marked dirty via
 *    needs_reset (such as by lack of FLR support)
 * Then attempt to perform that bus or slot reset.
 */
static void vfio_pci_dev_set_try_reset(struct vfio_device_set *dev_set)
{
        struct vfio_pci_core_device *cur;
        struct pci_dev *pdev;
        bool reset_done = false;

        if (!vfio_pci_dev_set_needs_reset(dev_set))
                return;

        pdev = vfio_pci_dev_set_resettable(dev_set);
        if (!pdev)
                return;

        /*
         * Some of the devices in the bus can be in the runtime suspended
         * state. Increment the usage count for all the devices in the dev_set
         * before reset and decrement the same after reset.
         */
        if (!disable_idle_d3 && vfio_pci_dev_set_pm_runtime_get(dev_set))
                return;

        if (!pci_reset_bus(pdev))
                reset_done = true;

        list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list) {
                if (reset_done)
                        cur->needs_reset = false;

                if (!disable_idle_d3)
                        pm_runtime_put(&cur->pdev->dev);
        }
}

void vfio_pci_core_set_params(bool is_nointxmask, bool is_disable_vga,
                              bool is_disable_idle_d3)
{
        nointxmask = is_nointxmask;
        disable_vga = is_disable_vga;
        disable_idle_d3 = is_disable_idle_d3;
}
EXPORT_SYMBOL_GPL(vfio_pci_core_set_params);

static void vfio_pci_core_cleanup(void)
{
        vfio_pci_uninit_perm_bits();
}

static int __init vfio_pci_core_init(void)
{
        /* Allocate shared config space permission data used by all devices */
        return vfio_pci_init_perm_bits();
}

module_init(vfio_pci_core_init);
module_exit(vfio_pci_core_cleanup);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);