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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2020, Red Hat, Inc.
   4  */
   5 #include <fcntl.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <sys/ioctl.h>
  10
  11 #include "test_util.h"
  12 #include "kvm_util.h"
  13 #include "processor.h"
  14
  15 static bool is_kvm_controlled_msr(uint32_t msr)
  16 {
  17         return msr == MSR_IA32_VMX_CR0_FIXED1 || msr == MSR_IA32_VMX_CR4_FIXED1;
  18 }
  19
  20 /*
  21  * For VMX MSRs with a "true" variant, KVM requires userspace to set the "true"
  22  * MSR, and doesn't allow setting the hidden version.
  23  */
  24 static bool is_hidden_vmx_msr(uint32_t msr)
  25 {
  26         switch (msr) {
  27         case MSR_IA32_VMX_PINBASED_CTLS:
  28         case MSR_IA32_VMX_PROCBASED_CTLS:
  29         case MSR_IA32_VMX_EXIT_CTLS:
  30         case MSR_IA32_VMX_ENTRY_CTLS:
  31                 return true;
  32         default:
  33                 return false;
  34         }
  35 }
  36
  37 static bool is_quirked_msr(uint32_t msr)
  38 {
  39         return msr != MSR_AMD64_DE_CFG;
  40 }
  41
  42 static void test_feature_msr(uint32_t msr)
  43 {
  44         const uint64_t supported_mask = kvm_get_feature_msr(msr);
  45         uint64_t reset_value = is_quirked_msr(msr) ? supported_mask : 0;
  46         struct kvm_vcpu *vcpu;
  47         struct kvm_vm *vm;
  48
  49         /*
  50          * Don't bother testing KVM-controlled MSRs beyond verifying that the
  51          * MSR can be read from userspace.  Any value is effectively legal, as
  52          * KVM is bound by x86 architecture, not by ABI.
  53          */
  54         if (is_kvm_controlled_msr(msr))
  55                 return;
  56
  57         /*
  58          * More goofy behavior.  KVM reports the host CPU's actual revision ID,
  59          * but initializes the vCPU's revision ID to an arbitrary value.
  60          */
  61         if (msr == MSR_IA32_UCODE_REV)
  62                 reset_value = host_cpu_is_intel ? 0x100000000ULL : 0x01000065;
  63
  64         /*
  65          * For quirked MSRs, KVM's ABI is to initialize the vCPU's value to the
  66          * full set of features supported by KVM.  For non-quirked MSRs, and
  67          * when the quirk is disabled, KVM must zero-initialize the MSR and let
  68          * userspace do the configuration.
  69          */
  70         vm = vm_create_with_one_vcpu(&vcpu, NULL);
  71         TEST_ASSERT(vcpu_get_msr(vcpu, msr) == reset_value,
  72                     "Wanted 0x%lx for %squirked MSR 0x%x, got 0x%lx",
  73                     reset_value, is_quirked_msr(msr) ? "" : "non-", msr,
  74                     vcpu_get_msr(vcpu, msr));
  75         if (!is_hidden_vmx_msr(msr))
  76                 vcpu_set_msr(vcpu, msr, supported_mask);
  77         kvm_vm_free(vm);
  78
  79         if (is_hidden_vmx_msr(msr))
  80                 return;
  81
  82         if (!kvm_has_cap(KVM_CAP_DISABLE_QUIRKS2) ||
  83             !(kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) & KVM_X86_QUIRK_STUFF_FEATURE_MSRS))
  84                 return;
  85
  86         vm = vm_create(1);
  87         vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, KVM_X86_QUIRK_STUFF_FEATURE_MSRS);
  88
  89         vcpu = vm_vcpu_add(vm, 0, NULL);
  90         TEST_ASSERT(!vcpu_get_msr(vcpu, msr),
  91                     "Quirk disabled, wanted '0' for MSR 0x%x, got 0x%lx",
  92                     msr, vcpu_get_msr(vcpu, msr));
  93         kvm_vm_free(vm);
  94 }
  95
  96 int main(int argc, char *argv[])
  97 {
  98         const struct kvm_msr_list *feature_list;
  99         int i;
 100
 101         /*
 102          * Skip the entire test if MSR_FEATURES isn't supported, other tests
 103          * will cover the "regular" list of MSRs, the coverage here is purely
 104          * opportunistic and not interesting on its own.
 105          */
 106         TEST_REQUIRE(kvm_has_cap(KVM_CAP_GET_MSR_FEATURES));
 107
 108         (void)kvm_get_msr_index_list();
 109
 110         feature_list = kvm_get_feature_msr_index_list();
 111         for (i = 0; i < feature_list->nmsrs; i++)
 112                 test_feature_msr(feature_list->indices[i]);
 113 }