tools/testing/selftests/kvm/x86_64/set_sregs_test.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * KVM_SET_SREGS tests
   4  *
   5  * Copyright (C) 2018, Google LLC.
   6  *
   7  * This is a regression test for the bug fixed by the following commit:
   8  * d3802286fa0f ("kvm: x86: Disallow illegal IA32_APIC_BASE MSR values")
   9  *
  10  * That bug allowed a user-mode program that called the KVM_SET_SREGS
  11  * ioctl to put a VCPU's local APIC into an invalid state.
  12  */
  13 #include <fcntl.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <sys/ioctl.h>
  18
  19 #include "test_util.h"
  20
  21 #include "kvm_util.h"
  22 #include "processor.h"
  23
  24 #define TEST_INVALID_CR_BIT(vcpu, cr, orig, bit)                                \
  25 do {                                                                            \
  26         struct kvm_sregs new;                                                   \
  27         int rc;                                                                 \
  28                                                                                 \
  29         /* Skip the sub-test, the feature/bit is supported. */                  \
  30         if (orig.cr & bit)                                                      \
  31                 break;                                                          \
  32                                                                                 \
  33         memcpy(&new, &orig, sizeof(sregs));                                     \
  34         new.cr |= bit;                                                          \
  35                                                                                 \
  36         rc = _vcpu_sregs_set(vcpu, &new);                                       \
  37         TEST_ASSERT(rc, "KVM allowed invalid " #cr " bit (0x%lx)", bit);        \
  38                                                                                 \
  39         /* Sanity check that KVM didn't change anything. */                     \
  40         vcpu_sregs_get(vcpu, &new);                                             \
  41         TEST_ASSERT(!memcmp(&new, &orig, sizeof(new)), "KVM modified sregs");   \
  42 } while (0)
  43
  44 static uint64_t calc_supported_cr4_feature_bits(void)
  45 {
  46         uint64_t cr4;
  47
  48         cr4 = X86_CR4_VME | X86_CR4_PVI | X86_CR4_TSD | X86_CR4_DE |
  49               X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE | X86_CR4_PGE |
  50               X86_CR4_PCE | X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT;
  51         if (kvm_cpu_has(X86_FEATURE_UMIP))
  52                 cr4 |= X86_CR4_UMIP;
  53         if (kvm_cpu_has(X86_FEATURE_LA57))
  54                 cr4 |= X86_CR4_LA57;
  55         if (kvm_cpu_has(X86_FEATURE_VMX))
  56                 cr4 |= X86_CR4_VMXE;
  57         if (kvm_cpu_has(X86_FEATURE_SMX))
  58                 cr4 |= X86_CR4_SMXE;
  59         if (kvm_cpu_has(X86_FEATURE_FSGSBASE))
  60                 cr4 |= X86_CR4_FSGSBASE;
  61         if (kvm_cpu_has(X86_FEATURE_PCID))
  62                 cr4 |= X86_CR4_PCIDE;
  63         if (kvm_cpu_has(X86_FEATURE_XSAVE))
  64                 cr4 |= X86_CR4_OSXSAVE;
  65         if (kvm_cpu_has(X86_FEATURE_SMEP))
  66                 cr4 |= X86_CR4_SMEP;
  67         if (kvm_cpu_has(X86_FEATURE_SMAP))
  68                 cr4 |= X86_CR4_SMAP;
  69         if (kvm_cpu_has(X86_FEATURE_PKU))
  70                 cr4 |= X86_CR4_PKE;
  71
  72         return cr4;
  73 }
  74
  75 int main(int argc, char *argv[])
  76 {
  77         struct kvm_sregs sregs;
  78         struct kvm_vcpu *vcpu;
  79         struct kvm_vm *vm;
  80         uint64_t cr4;
  81         int rc, i;
  82
  83         /*
  84          * Create a dummy VM, specifically to avoid doing KVM_SET_CPUID2, and
  85          * use it to verify all supported CR4 bits can be set prior to defining
  86          * the vCPU model, i.e. without doing KVM_SET_CPUID2.
  87          */
  88         vm = vm_create_barebones();
  89         vcpu = __vm_vcpu_add(vm, 0);
  90
  91         vcpu_sregs_get(vcpu, &sregs);
  92
  93         sregs.cr0 = 0;
  94         sregs.cr4 |= calc_supported_cr4_feature_bits();
  95         cr4 = sregs.cr4;
  96
  97         rc = _vcpu_sregs_set(vcpu, &sregs);
  98         TEST_ASSERT(!rc, "Failed to set supported CR4 bits (0x%lx)", cr4);
  99
 100         vcpu_sregs_get(vcpu, &sregs);
 101         TEST_ASSERT(sregs.cr4 == cr4, "sregs.CR4 (0x%llx) != CR4 (0x%lx)",
 102                     sregs.cr4, cr4);
 103
 104         /* Verify all unsupported features are rejected by KVM. */
 105         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_UMIP);
 106         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_LA57);
 107         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_VMXE);
 108         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_SMXE);
 109         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_FSGSBASE);
 110         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_PCIDE);
 111         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_OSXSAVE);
 112         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_SMEP);
 113         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_SMAP);
 114         TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_PKE);
 115
 116         for (i = 32; i < 64; i++)
 117                 TEST_INVALID_CR_BIT(vcpu, cr0, sregs, BIT(i));
 118
 119         /* NW without CD is illegal, as is PG without PE. */
 120         TEST_INVALID_CR_BIT(vcpu, cr0, sregs, X86_CR0_NW);
 121         TEST_INVALID_CR_BIT(vcpu, cr0, sregs, X86_CR0_PG);
 122
 123         kvm_vm_free(vm);
 124
 125         /* Create a "real" VM and verify APIC_BASE can be set. */
 126         vm = vm_create_with_one_vcpu(&vcpu, NULL);
 127
 128         vcpu_sregs_get(vcpu, &sregs);
 129         sregs.apic_base = 1 << 10;
 130         rc = _vcpu_sregs_set(vcpu, &sregs);
 131         TEST_ASSERT(rc, "Set IA32_APIC_BASE to %llx (invalid)",
 132                     sregs.apic_base);
 133         sregs.apic_base = 1 << 11;
 134         rc = _vcpu_sregs_set(vcpu, &sregs);
 135         TEST_ASSERT(!rc, "Couldn't set IA32_APIC_BASE to %llx (valid)",
 136                     sregs.apic_base);
 137
 138         kvm_vm_free(vm);
 139
 140         return 0;
 141 }