LXR linux/tools/testing/selftests/kvm/x86_64/xss_msr

   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
  20bool 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
  38int 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}
  77