arch/x86/xen/enlighten_hvm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/acpi.h>
   4 #include <linux/cpu.h>
   5 #include <linux/kexec.h>
   6 #include <linux/memblock.h>
   7
   8 #include <xen/features.h>
   9 #include <xen/events.h>
  10 #include <xen/interface/memory.h>
  11
  12 #include <asm/cpu.h>
  13 #include <asm/smp.h>
  14 #include <asm/reboot.h>
  15 #include <asm/setup.h>
  16 #include <asm/idtentry.h>
  17 #include <asm/hypervisor.h>
  18 #include <asm/e820/api.h>
  19 #include <asm/early_ioremap.h>
  20
  21 #include <asm/xen/cpuid.h>
  22 #include <asm/xen/hypervisor.h>
  23 #include <asm/xen/page.h>
  24
  25 #include "xen-ops.h"
  26 #include "mmu.h"
  27 #include "smp.h"
  28
  29 static unsigned long shared_info_pfn;
  30
  31 void xen_hvm_init_shared_info(void)
  32 {
  33         struct xen_add_to_physmap xatp;
  34
  35         xatp.domid = DOMID_SELF;
  36         xatp.idx = 0;
  37         xatp.space = XENMAPSPACE_shared_info;
  38         xatp.gpfn = shared_info_pfn;
  39         if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
  40                 BUG();
  41 }
  42
  43 static void __init reserve_shared_info(void)
  44 {
  45         u64 pa;
  46
  47         /*
  48          * Search for a free page starting at 4kB physical address.
  49          * Low memory is preferred to avoid an EPT large page split up
  50          * by the mapping.
  51          * Starting below X86_RESERVE_LOW (usually 64kB) is fine as
  52          * the BIOS used for HVM guests is well behaved and won't
  53          * clobber memory other than the first 4kB.
  54          */
  55         for (pa = PAGE_SIZE;
  56              !e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
  57              memblock_is_reserved(pa);
  58              pa += PAGE_SIZE)
  59                 ;
  60
  61         shared_info_pfn = PHYS_PFN(pa);
  62
  63         memblock_reserve(pa, PAGE_SIZE);
  64         HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
  65 }
  66
  67 static void __init xen_hvm_init_mem_mapping(void)
  68 {
  69         early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
  70         HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
  71
  72         /*
  73          * The virtual address of the shared_info page has changed, so
  74          * the vcpu_info pointer for VCPU 0 is now stale.
  75          *
  76          * The prepare_boot_cpu callback will re-initialize it via
  77          * xen_vcpu_setup, but we can't rely on that to be called for
  78          * old Xen versions (xen_have_vector_callback == 0).
  79          *
  80          * It is, in any case, bad to have a stale vcpu_info pointer
  81          * so reset it now.
  82          */
  83         xen_vcpu_info_reset(0);
  84 }
  85
  86 static void __init init_hvm_pv_info(void)
  87 {
  88         int major, minor;
  89         uint32_t eax, ebx, ecx, edx, base;
  90
  91         base = xen_cpuid_base();
  92         eax = cpuid_eax(base + 1);
  93
  94         major = eax >> 16;
  95         minor = eax & 0xffff;
  96         printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
  97
  98         xen_domain_type = XEN_HVM_DOMAIN;
  99
 100         /* PVH set up hypercall page in xen_prepare_pvh(). */
 101         if (xen_pvh_domain())
 102                 pv_info.name = "Xen PVH";
 103         else {
 104                 u64 pfn;
 105                 uint32_t msr;
 106
 107                 pv_info.name = "Xen HVM";
 108                 msr = cpuid_ebx(base + 2);
 109                 pfn = __pa(hypercall_page);
 110                 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
 111         }
 112
 113         xen_setup_features();
 114
 115         cpuid(base + 4, &eax, &ebx, &ecx, &edx);
 116         if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
 117                 this_cpu_write(xen_vcpu_id, ebx);
 118         else
 119                 this_cpu_write(xen_vcpu_id, smp_processor_id());
 120 }
 121
 122 DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
 123 {
 124         struct pt_regs *old_regs = set_irq_regs(regs);
 125
 126         inc_irq_stat(irq_hv_callback_count);
 127
 128         xen_hvm_evtchn_do_upcall();
 129
 130         set_irq_regs(old_regs);
 131 }
 132
 133 #ifdef CONFIG_KEXEC_CORE
 134 static void xen_hvm_shutdown(void)
 135 {
 136         native_machine_shutdown();
 137         if (kexec_in_progress)
 138                 xen_reboot(SHUTDOWN_soft_reset);
 139 }
 140
 141 static void xen_hvm_crash_shutdown(struct pt_regs *regs)
 142 {
 143         native_machine_crash_shutdown(regs);
 144         xen_reboot(SHUTDOWN_soft_reset);
 145 }
 146 #endif
 147
 148 static int xen_cpu_up_prepare_hvm(unsigned int cpu)
 149 {
 150         int rc = 0;
 151
 152         /*
 153          * This can happen if CPU was offlined earlier and
 154          * offlining timed out in common_cpu_die().
 155          */
 156         if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
 157                 xen_smp_intr_free(cpu);
 158                 xen_uninit_lock_cpu(cpu);
 159         }
 160
 161         if (cpu_acpi_id(cpu) != U32_MAX)
 162                 per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
 163         else
 164                 per_cpu(xen_vcpu_id, cpu) = cpu;
 165         rc = xen_vcpu_setup(cpu);
 166         if (rc)
 167                 return rc;
 168
 169         if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
 170                 xen_setup_timer(cpu);
 171
 172         rc = xen_smp_intr_init(cpu);
 173         if (rc) {
 174                 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
 175                      cpu, rc);
 176         }
 177         return rc;
 178 }
 179
 180 static int xen_cpu_dead_hvm(unsigned int cpu)
 181 {
 182         xen_smp_intr_free(cpu);
 183
 184         if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
 185                 xen_teardown_timer(cpu);
 186
 187        return 0;
 188 }
 189
 190 static void __init xen_hvm_guest_init(void)
 191 {
 192         if (xen_pv_domain())
 193                 return;
 194
 195         init_hvm_pv_info();
 196
 197         reserve_shared_info();
 198         xen_hvm_init_shared_info();
 199
 200         /*
 201          * xen_vcpu is a pointer to the vcpu_info struct in the shared_info
 202          * page, we use it in the event channel upcall and in some pvclock
 203          * related functions.
 204          */
 205         xen_vcpu_info_reset(0);
 206
 207         xen_panic_handler_init();
 208
 209         if (xen_feature(XENFEAT_hvm_callback_vector))
 210                 xen_have_vector_callback = 1;
 211
 212         xen_hvm_smp_init();
 213         WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
 214         xen_unplug_emulated_devices();
 215         x86_init.irqs.intr_init = xen_init_IRQ;
 216         xen_hvm_init_time_ops();
 217         xen_hvm_init_mmu_ops();
 218
 219 #ifdef CONFIG_KEXEC_CORE
 220         machine_ops.shutdown = xen_hvm_shutdown;
 221         machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
 222 #endif
 223 }
 224
 225 static __init int xen_parse_nopv(char *arg)
 226 {
 227         pr_notice("\"xen_nopv\" is deprecated, please use \"nopv\" instead\n");
 228
 229         if (xen_cpuid_base())
 230                 nopv = true;
 231         return 0;
 232 }
 233 early_param("xen_nopv", xen_parse_nopv);
 234
 235 bool __init xen_hvm_need_lapic(void)
 236 {
 237         if (xen_pv_domain())
 238                 return false;
 239         if (!xen_hvm_domain())
 240                 return false;
 241         if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback)
 242                 return false;
 243         return true;
 244 }
 245
 246 static __init void xen_hvm_guest_late_init(void)
 247 {
 248 #ifdef CONFIG_XEN_PVH
 249         /* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
 250         if (!xen_pvh &&
 251             (x86_platform.legacy.rtc || !x86_platform.legacy.no_vga))
 252                 return;
 253
 254         /* PVH detected. */
 255         xen_pvh = true;
 256
 257         if (nopv)
 258                 panic("\"nopv\" and \"xen_nopv\" parameters are unsupported in PVH guest.");
 259
 260         /* Make sure we don't fall back to (default) ACPI_IRQ_MODEL_PIC. */
 261         if (!nr_ioapics && acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 262                 acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
 263
 264         machine_ops.emergency_restart = xen_emergency_restart;
 265         pv_info.name = "Xen PVH";
 266 #endif
 267 }
 268
 269 static uint32_t __init xen_platform_hvm(void)
 270 {
 271         uint32_t xen_domain = xen_cpuid_base();
 272         struct x86_hyper_init *h = &x86_hyper_xen_hvm.init;
 273
 274         if (xen_pv_domain())
 275                 return 0;
 276
 277         if (xen_pvh_domain() && nopv) {
 278                 /* Guest booting via the Xen-PVH boot entry goes here */
 279                 pr_info("\"nopv\" parameter is ignored in PVH guest\n");
 280                 nopv = false;
 281         } else if (nopv && xen_domain) {
 282                 /*
 283                  * Guest booting via normal boot entry (like via grub2) goes
 284                  * here.
 285                  *
 286                  * Use interface functions for bare hardware if nopv,
 287                  * xen_hvm_guest_late_init is an exception as we need to
 288                  * detect PVH and panic there.
 289                  */
 290                 h->init_platform = x86_init_noop;
 291                 h->x2apic_available = bool_x86_init_noop;
 292                 h->init_mem_mapping = x86_init_noop;
 293                 h->init_after_bootmem = x86_init_noop;
 294                 h->guest_late_init = xen_hvm_guest_late_init;
 295                 x86_hyper_xen_hvm.runtime.pin_vcpu = x86_op_int_noop;
 296         }
 297         return xen_domain;
 298 }
 299
 300 struct hypervisor_x86 x86_hyper_xen_hvm __initdata = {
 301         .name                   = "Xen HVM",
 302         .detect                 = xen_platform_hvm,
 303         .type                   = X86_HYPER_XEN_HVM,
 304         .init.init_platform     = xen_hvm_guest_init,
 305         .init.x2apic_available  = xen_x2apic_para_available,
 306         .init.init_mem_mapping  = xen_hvm_init_mem_mapping,
 307         .init.guest_late_init   = xen_hvm_guest_late_init,
 308         .runtime.pin_vcpu       = xen_pin_vcpu,
 309         .ignore_nopv            = true,
 310 };