arch/s390/kvm/pv.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Hosting Protected Virtual Machines
   4  *
   5  * Copyright IBM Corp. 2019, 2020
   6  *    Author(s): Janosch Frank <[email protected]>
   7  */
   8 #include <linux/kvm.h>
   9 #include <linux/kvm_host.h>
  10 #include <linux/pagemap.h>
  11 #include <linux/sched/signal.h>
  12 #include <asm/gmap.h>
  13 #include <asm/uv.h>
  14 #include <asm/mman.h>
  15 #include "kvm-s390.h"
  16
  17 int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
  18 {
  19         int cc;
  20
  21         if (!kvm_s390_pv_cpu_get_handle(vcpu))
  22                 return 0;
  23
  24         cc = uv_cmd_nodata(kvm_s390_pv_cpu_get_handle(vcpu), UVC_CMD_DESTROY_SEC_CPU, rc, rrc);
  25
  26         KVM_UV_EVENT(vcpu->kvm, 3, "PROTVIRT DESTROY VCPU %d: rc %x rrc %x",
  27                      vcpu->vcpu_id, *rc, *rrc);
  28         WARN_ONCE(cc, "protvirt destroy cpu failed rc %x rrc %x", *rc, *rrc);
  29
  30         /* Intended memory leak for something that should never happen. */
  31         if (!cc)
  32                 free_pages(vcpu->arch.pv.stor_base,
  33                            get_order(uv_info.guest_cpu_stor_len));
  34
  35         free_page(sida_origin(vcpu->arch.sie_block));
  36         vcpu->arch.sie_block->pv_handle_cpu = 0;
  37         vcpu->arch.sie_block->pv_handle_config = 0;
  38         memset(&vcpu->arch.pv, 0, sizeof(vcpu->arch.pv));
  39         vcpu->arch.sie_block->sdf = 0;
  40         /*
  41          * The sidad field (for sdf == 2) is now the gbea field (for sdf == 0).
  42          * Use the reset value of gbea to avoid leaking the kernel pointer of
  43          * the just freed sida.
  44          */
  45         vcpu->arch.sie_block->gbea = 1;
  46         kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
  47
  48         return cc ? EIO : 0;
  49 }
  50
  51 int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
  52 {
  53         struct uv_cb_csc uvcb = {
  54                 .header.cmd = UVC_CMD_CREATE_SEC_CPU,
  55                 .header.len = sizeof(uvcb),
  56         };
  57         int cc;
  58
  59         if (kvm_s390_pv_cpu_get_handle(vcpu))
  60                 return -EINVAL;
  61
  62         vcpu->arch.pv.stor_base = __get_free_pages(GFP_KERNEL_ACCOUNT,
  63                                                    get_order(uv_info.guest_cpu_stor_len));
  64         if (!vcpu->arch.pv.stor_base)
  65                 return -ENOMEM;
  66
  67         /* Input */
  68         uvcb.guest_handle = kvm_s390_pv_get_handle(vcpu->kvm);
  69         uvcb.num = vcpu->arch.sie_block->icpua;
  70         uvcb.state_origin = (u64)vcpu->arch.sie_block;
  71         uvcb.stor_origin = (u64)vcpu->arch.pv.stor_base;
  72
  73         /* Alloc Secure Instruction Data Area Designation */
  74         vcpu->arch.sie_block->sidad = __get_free_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
  75         if (!vcpu->arch.sie_block->sidad) {
  76                 free_pages(vcpu->arch.pv.stor_base,
  77                            get_order(uv_info.guest_cpu_stor_len));
  78                 return -ENOMEM;
  79         }
  80
  81         cc = uv_call(0, (u64)&uvcb);
  82         *rc = uvcb.header.rc;
  83         *rrc = uvcb.header.rrc;
  84         KVM_UV_EVENT(vcpu->kvm, 3,
  85                      "PROTVIRT CREATE VCPU: cpu %d handle %llx rc %x rrc %x",
  86                      vcpu->vcpu_id, uvcb.cpu_handle, uvcb.header.rc,
  87                      uvcb.header.rrc);
  88
  89         if (cc) {
  90                 u16 dummy;
  91
  92                 kvm_s390_pv_destroy_cpu(vcpu, &dummy, &dummy);
  93                 return -EIO;
  94         }
  95
  96         /* Output */
  97         vcpu->arch.pv.handle = uvcb.cpu_handle;
  98         vcpu->arch.sie_block->pv_handle_cpu = uvcb.cpu_handle;
  99         vcpu->arch.sie_block->pv_handle_config = kvm_s390_pv_get_handle(vcpu->kvm);
 100         vcpu->arch.sie_block->sdf = 2;
 101         kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
 102         return 0;
 103 }
 104
 105 /* only free resources when the destroy was successful */
 106 static void kvm_s390_pv_dealloc_vm(struct kvm *kvm)
 107 {
 108         vfree(kvm->arch.pv.stor_var);
 109         free_pages(kvm->arch.pv.stor_base,
 110                    get_order(uv_info.guest_base_stor_len));
 111         memset(&kvm->arch.pv, 0, sizeof(kvm->arch.pv));
 112 }
 113
 114 static int kvm_s390_pv_alloc_vm(struct kvm *kvm)
 115 {
 116         unsigned long base = uv_info.guest_base_stor_len;
 117         unsigned long virt = uv_info.guest_virt_var_stor_len;
 118         unsigned long npages = 0, vlen = 0;
 119         struct kvm_memory_slot *memslot;
 120
 121         kvm->arch.pv.stor_var = NULL;
 122         kvm->arch.pv.stor_base = __get_free_pages(GFP_KERNEL_ACCOUNT, get_order(base));
 123         if (!kvm->arch.pv.stor_base)
 124                 return -ENOMEM;
 125
 126         /*
 127          * Calculate current guest storage for allocation of the
 128          * variable storage, which is based on the length in MB.
 129          *
 130          * Slots are sorted by GFN
 131          */
 132         mutex_lock(&kvm->slots_lock);
 133         memslot = kvm_memslots(kvm)->memslots;
 134         npages = memslot->base_gfn + memslot->npages;
 135         mutex_unlock(&kvm->slots_lock);
 136
 137         kvm->arch.pv.guest_len = npages * PAGE_SIZE;
 138
 139         /* Allocate variable storage */
 140         vlen = ALIGN(virt * ((npages * PAGE_SIZE) / HPAGE_SIZE), PAGE_SIZE);
 141         vlen += uv_info.guest_virt_base_stor_len;
 142         /*
 143          * The Create Secure Configuration Ultravisor Call does not support
 144          * using large pages for the virtual memory area.
 145          * This is a hardware limitation.
 146          */
 147         kvm->arch.pv.stor_var = vmalloc_no_huge(vlen);
 148         if (!kvm->arch.pv.stor_var)
 149                 goto out_err;
 150         return 0;
 151
 152 out_err:
 153         kvm_s390_pv_dealloc_vm(kvm);
 154         return -ENOMEM;
 155 }
 156
 157 /* this should not fail, but if it does, we must not free the donated memory */
 158 int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
 159 {
 160         int cc;
 161
 162         /* make all pages accessible before destroying the guest */
 163         s390_reset_acc(kvm->mm);
 164
 165         cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
 166                            UVC_CMD_DESTROY_SEC_CONF, rc, rrc);
 167         WRITE_ONCE(kvm->arch.gmap->guest_handle, 0);
 168         atomic_set(&kvm->mm->context.is_protected, 0);
 169         KVM_UV_EVENT(kvm, 3, "PROTVIRT DESTROY VM: rc %x rrc %x", *rc, *rrc);
 170         WARN_ONCE(cc, "protvirt destroy vm failed rc %x rrc %x", *rc, *rrc);
 171         /* Inteded memory leak on "impossible" error */
 172         if (!cc)
 173                 kvm_s390_pv_dealloc_vm(kvm);
 174         return cc ? -EIO : 0;
 175 }
 176
 177 int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
 178 {
 179         struct uv_cb_cgc uvcb = {
 180                 .header.cmd = UVC_CMD_CREATE_SEC_CONF,
 181                 .header.len = sizeof(uvcb)
 182         };
 183         int cc, ret;
 184         u16 dummy;
 185
 186         ret = kvm_s390_pv_alloc_vm(kvm);
 187         if (ret)
 188                 return ret;
 189
 190         /* Inputs */
 191         uvcb.guest_stor_origin = 0; /* MSO is 0 for KVM */
 192         uvcb.guest_stor_len = kvm->arch.pv.guest_len;
 193         uvcb.guest_asce = kvm->arch.gmap->asce;
 194         uvcb.guest_sca = (unsigned long)kvm->arch.sca;
 195         uvcb.conf_base_stor_origin = (u64)kvm->arch.pv.stor_base;
 196         uvcb.conf_virt_stor_origin = (u64)kvm->arch.pv.stor_var;
 197
 198         cc = uv_call_sched(0, (u64)&uvcb);
 199         *rc = uvcb.header.rc;
 200         *rrc = uvcb.header.rrc;
 201         KVM_UV_EVENT(kvm, 3, "PROTVIRT CREATE VM: handle %llx len %llx rc %x rrc %x",
 202                      uvcb.guest_handle, uvcb.guest_stor_len, *rc, *rrc);
 203
 204         /* Outputs */
 205         kvm->arch.pv.handle = uvcb.guest_handle;
 206
 207         if (cc) {
 208                 if (uvcb.header.rc & UVC_RC_NEED_DESTROY)
 209                         kvm_s390_pv_deinit_vm(kvm, &dummy, &dummy);
 210                 else
 211                         kvm_s390_pv_dealloc_vm(kvm);
 212                 return -EIO;
 213         }
 214         kvm->arch.gmap->guest_handle = uvcb.guest_handle;
 215         return 0;
 216 }
 217
 218 int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc,
 219                               u16 *rrc)
 220 {
 221         struct uv_cb_ssc uvcb = {
 222                 .header.cmd = UVC_CMD_SET_SEC_CONF_PARAMS,
 223                 .header.len = sizeof(uvcb),
 224                 .sec_header_origin = (u64)hdr,
 225                 .sec_header_len = length,
 226                 .guest_handle = kvm_s390_pv_get_handle(kvm),
 227         };
 228         int cc = uv_call(0, (u64)&uvcb);
 229
 230         *rc = uvcb.header.rc;
 231         *rrc = uvcb.header.rrc;
 232         KVM_UV_EVENT(kvm, 3, "PROTVIRT VM SET PARMS: rc %x rrc %x",
 233                      *rc, *rrc);
 234         if (!cc)
 235                 atomic_set(&kvm->mm->context.is_protected, 1);
 236         return cc ? -EINVAL : 0;
 237 }
 238
 239 static int unpack_one(struct kvm *kvm, unsigned long addr, u64 tweak,
 240                       u64 offset, u16 *rc, u16 *rrc)
 241 {
 242         struct uv_cb_unp uvcb = {
 243                 .header.cmd = UVC_CMD_UNPACK_IMG,
 244                 .header.len = sizeof(uvcb),
 245                 .guest_handle = kvm_s390_pv_get_handle(kvm),
 246                 .gaddr = addr,
 247                 .tweak[0] = tweak,
 248                 .tweak[1] = offset,
 249         };
 250         int ret = gmap_make_secure(kvm->arch.gmap, addr, &uvcb);
 251
 252         *rc = uvcb.header.rc;
 253         *rrc = uvcb.header.rrc;
 254
 255         if (ret && ret != -EAGAIN)
 256                 KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: failed addr %llx with rc %x rrc %x",
 257                              uvcb.gaddr, *rc, *rrc);
 258         return ret;
 259 }
 260
 261 int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size,
 262                        unsigned long tweak, u16 *rc, u16 *rrc)
 263 {
 264         u64 offset = 0;
 265         int ret = 0;
 266
 267         if (addr & ~PAGE_MASK || !size || size & ~PAGE_MASK)
 268                 return -EINVAL;
 269
 270         KVM_UV_EVENT(kvm, 3, "PROTVIRT VM UNPACK: start addr %lx size %lx",
 271                      addr, size);
 272
 273         while (offset < size) {
 274                 ret = unpack_one(kvm, addr, tweak, offset, rc, rrc);
 275                 if (ret == -EAGAIN) {
 276                         cond_resched();
 277                         if (fatal_signal_pending(current))
 278                                 break;
 279                         continue;
 280                 }
 281                 if (ret)
 282                         break;
 283                 addr += PAGE_SIZE;
 284                 offset += PAGE_SIZE;
 285         }
 286         if (!ret)
 287                 KVM_UV_EVENT(kvm, 3, "%s", "PROTVIRT VM UNPACK: successful");
 288         return ret;
 289 }
 290
 291 int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state)
 292 {
 293         struct uv_cb_cpu_set_state uvcb = {
 294                 .header.cmd     = UVC_CMD_CPU_SET_STATE,
 295                 .header.len     = sizeof(uvcb),
 296                 .cpu_handle     = kvm_s390_pv_cpu_get_handle(vcpu),
 297                 .state          = state,
 298         };
 299         int cc;
 300
 301         cc = uv_call(0, (u64)&uvcb);
 302         KVM_UV_EVENT(vcpu->kvm, 3, "PROTVIRT SET CPU %d STATE %d rc %x rrc %x",
 303                      vcpu->vcpu_id, state, uvcb.header.rc, uvcb.header.rrc);
 304         if (cc)
 305                 return -EINVAL;
 306         return 0;
 307 }