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 #include <sys/ioctl.h>
   8
   9 #include "test_util.h"
  10 #include "kvm_util.h"
  11 #include "vmx.h"
  12
  13 #define MSR_BITS      64
  14
  15 int main(int argc, char *argv[])
  16 {
  17         bool xss_in_msr_list;
  18         struct kvm_vm *vm;
  19         struct kvm_vcpu *vcpu;
  20         uint64_t xss_val;
  21         int i, r;
  22
  23         /* Create VM */
  24         vm = vm_create_with_one_vcpu(&vcpu, NULL);
  25
  26         TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_XSAVES));
  27
  28         xss_val = vcpu_get_msr(vcpu, MSR_IA32_XSS);
  29         TEST_ASSERT(xss_val == 0,
  30                     "MSR_IA32_XSS should be initialized to zero");
  31
  32         vcpu_set_msr(vcpu, MSR_IA32_XSS, xss_val);
  33
  34         /*
  35          * At present, KVM only supports a guest IA32_XSS value of 0. Verify
  36          * that trying to set the guest IA32_XSS to an unsupported value fails.
  37          * Also, in the future when a non-zero value succeeds check that
  38          * IA32_XSS is in the list of MSRs to save/restore.
  39          */
  40         xss_in_msr_list = kvm_msr_is_in_save_restore_list(MSR_IA32_XSS);
  41         for (i = 0; i < MSR_BITS; ++i) {
  42                 r = _vcpu_set_msr(vcpu, MSR_IA32_XSS, 1ull << i);
  43
  44                 /*
  45                  * Setting a list of MSRs returns the entry that "faulted", or
  46                  * the last entry +1 if all MSRs were successfully written.
  47                  */
  48                 TEST_ASSERT(!r || r == 1, KVM_IOCTL_ERROR(KVM_SET_MSRS, r));
  49                 TEST_ASSERT(r != 1 || xss_in_msr_list,
  50                             "IA32_XSS was able to be set, but was not in save/restore list");
  51         }
  52
  53         kvm_vm_free(vm);
  54 }