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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2019, Google LLC.
   4  *
   5  * Tests for the IA32_XSS MSR.
   6  */
   7
   8 #define _GNU_SOURCE /* for program_invocation_short_name */
   9 #include <sys/ioctl.h>
  10
  11 #include "test_util.h"
  12 #include "kvm_util.h"
  13 #include "vmx.h"
  14
  15 #define VCPU_ID       1
  16 #define MSR_BITS      64
  17
  18 #define X86_FEATURE_XSAVES      (1<<3)
  19
  20 bool is_supported_msr(u32 msr_index)
  21 {
  22         struct kvm_msr_list *list;
  23         bool found = false;
  24         int i;
  25
  26         list = kvm_get_msr_index_list();
  27         for (i = 0; i < list->nmsrs; ++i) {
  28                 if (list->indices[i] == msr_index) {
  29                         found = true;
  30                         break;
  31                 }
  32         }
  33
  34         free(list);
  35         return found;
  36 }
  37
  38 int main(int argc, char *argv[])
  39 {
  40         struct kvm_cpuid_entry2 *entry;
  41         bool xss_supported = false;
  42         struct kvm_vm *vm;
  43         uint64_t xss_val;
  44         int i, r;
  45
  46         /* Create VM */
  47         vm = vm_create_default(VCPU_ID, 0, 0);
  48
  49         if (kvm_get_cpuid_max_basic() >= 0xd) {
  50                 entry = kvm_get_supported_cpuid_index(0xd, 1);
  51                 xss_supported = entry && !!(entry->eax & X86_FEATURE_XSAVES);
  52         }
  53         if (!xss_supported) {
  54                 print_skip("IA32_XSS is not supported by the vCPU");
  55                 exit(KSFT_SKIP);
  56         }
  57
  58         xss_val = vcpu_get_msr(vm, VCPU_ID, MSR_IA32_XSS);
  59         TEST_ASSERT(xss_val == 0,
  60                     "MSR_IA32_XSS should be initialized to zero\n");
  61
  62         vcpu_set_msr(vm, VCPU_ID, MSR_IA32_XSS, xss_val);
  63         /*
  64          * At present, KVM only supports a guest IA32_XSS value of 0. Verify
  65          * that trying to set the guest IA32_XSS to an unsupported value fails.
  66          * Also, in the future when a non-zero value succeeds check that
  67          * IA32_XSS is in the KVM_GET_MSR_INDEX_LIST.
  68          */
  69         for (i = 0; i < MSR_BITS; ++i) {
  70                 r = _vcpu_set_msr(vm, VCPU_ID, MSR_IA32_XSS, 1ull << i);
  71                 TEST_ASSERT(r == 0 || is_supported_msr(MSR_IA32_XSS),
  72                             "IA32_XSS was able to be set, but was not found in KVM_GET_MSR_INDEX_LIST.\n");
  73         }
  74
  75         kvm_vm_free(vm);
  76 }