tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * XCR0 cpuid test
   4  *
   5  * Copyright (C) 2022, Google LLC.
   6  */
   7
   8 #include <fcntl.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <sys/ioctl.h>
  13
  14 #include "test_util.h"
  15
  16 #include "kvm_util.h"
  17 #include "processor.h"
  18
  19 /*
  20  * Assert that architectural dependency rules are satisfied, e.g. that AVX is
  21  * supported if and only if SSE is supported.
  22  */
  23 #define ASSERT_XFEATURE_DEPENDENCIES(supported_xcr0, xfeatures, dependencies)     \
  24 do {                                                                              \
  25         uint64_t __supported = (supported_xcr0) & ((xfeatures) | (dependencies)); \
  26                                                                                   \
  27         GUEST_ASSERT_3((__supported & (xfeatures)) != (xfeatures) ||              \
  28                        __supported == ((xfeatures) | (dependencies)),             \
  29                        __supported, (xfeatures), (dependencies));                 \
  30 } while (0)
  31
  32 /*
  33  * Assert that KVM reports a sane, usable as-is XCR0.  Architecturally, a CPU
  34  * isn't strictly required to _support_ all XFeatures related to a feature, but
  35  * at the same time XSETBV will #GP if bundled XFeatures aren't enabled and
  36  * disabled coherently.  E.g. a CPU can technically enumerate supported for
  37  * XTILE_CFG but not XTILE_DATA, but attempting to enable XTILE_CFG without
  38  * XTILE_DATA will #GP.
  39  */
  40 #define ASSERT_ALL_OR_NONE_XFEATURE(supported_xcr0, xfeatures)          \
  41 do {                                                                    \
  42         uint64_t __supported = (supported_xcr0) & (xfeatures);          \
  43                                                                         \
  44         GUEST_ASSERT_2(!__supported || __supported == (xfeatures),      \
  45                        __supported, (xfeatures));                       \
  46 } while (0)
  47
  48 static void guest_code(void)
  49 {
  50         uint64_t xcr0_reset;
  51         uint64_t supported_xcr0;
  52         int i, vector;
  53
  54         set_cr4(get_cr4() | X86_CR4_OSXSAVE);
  55
  56         xcr0_reset = xgetbv(0);
  57         supported_xcr0 = this_cpu_supported_xcr0();
  58
  59         GUEST_ASSERT(xcr0_reset == XFEATURE_MASK_FP);
  60
  61         /* Check AVX */
  62         ASSERT_XFEATURE_DEPENDENCIES(supported_xcr0,
  63                                      XFEATURE_MASK_YMM,
  64                                      XFEATURE_MASK_SSE);
  65
  66         /* Check MPX */
  67         ASSERT_ALL_OR_NONE_XFEATURE(supported_xcr0,
  68                                     XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR);
  69
  70         /* Check AVX-512 */
  71         ASSERT_XFEATURE_DEPENDENCIES(supported_xcr0,
  72                                      XFEATURE_MASK_AVX512,
  73                                      XFEATURE_MASK_SSE | XFEATURE_MASK_YMM);
  74         ASSERT_ALL_OR_NONE_XFEATURE(supported_xcr0,
  75                                     XFEATURE_MASK_AVX512);
  76
  77         /* Check AMX */
  78         ASSERT_ALL_OR_NONE_XFEATURE(supported_xcr0,
  79                                     XFEATURE_MASK_XTILE);
  80
  81         vector = xsetbv_safe(0, supported_xcr0);
  82         GUEST_ASSERT_2(!vector, supported_xcr0, vector);
  83
  84         for (i = 0; i < 64; i++) {
  85                 if (supported_xcr0 & BIT_ULL(i))
  86                         continue;
  87
  88                 vector = xsetbv_safe(0, supported_xcr0 | BIT_ULL(i));
  89                 GUEST_ASSERT_3(vector == GP_VECTOR, supported_xcr0, vector, BIT_ULL(i));
  90         }
  91
  92         GUEST_DONE();
  93 }
  94
  95 int main(int argc, char *argv[])
  96 {
  97         struct kvm_vcpu *vcpu;
  98         struct kvm_run *run;
  99         struct kvm_vm *vm;
 100         struct ucall uc;
 101
 102         TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_XSAVE));
 103
 104         vm = vm_create_with_one_vcpu(&vcpu, guest_code);
 105         run = vcpu->run;
 106
 107         vm_init_descriptor_tables(vm);
 108         vcpu_init_descriptor_tables(vcpu);
 109
 110         while (1) {
 111                 vcpu_run(vcpu);
 112
 113                 TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
 114                             "Unexpected exit reason: %u (%s),\n",
 115                             run->exit_reason,
 116                             exit_reason_str(run->exit_reason));
 117
 118                 switch (get_ucall(vcpu, &uc)) {
 119                 case UCALL_ABORT:
 120                         REPORT_GUEST_ASSERT_3(uc, "0x%lx 0x%lx 0x%lx");
 121                         break;
 122                 case UCALL_DONE:
 123                         goto done;
 124                 default:
 125                         TEST_FAIL("Unknown ucall %lu", uc.cmd);
 126                 }
 127         }
 128
 129 done:
 130         kvm_vm_free(vm);
 131         return 0;
 132 }