Test that the supported xfeatures, i.e. EDX:EAX of CPUID.(EAX=0DH,ECX=0),
don't set userspace up for failure.
Though it isn't architectural, test that the supported xfeatures
aren't set in a half baked state that will cause a #GP if used to
execute XSETBV.
Check that the rules for XCR0 described in the SDM vol 1, section
13.3 ENABLING THE XSAVE FEATURE SET AND XSAVE-ENABLED FEATURES, are
followed for the supported xfeatures too.
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/x86_64/xcr0_cpuid_test.c | 121 ++++++++++++++++++
2 files changed, 122 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 1750f91dd9362..e2e56c82b8a90 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -104,6 +104,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/vmx_tsc_adjust_test
TEST_GEN_PROGS_x86_64 += x86_64/vmx_nested_tsc_scaling_test
TEST_GEN_PROGS_x86_64 += x86_64/xapic_ipi_test
TEST_GEN_PROGS_x86_64 += x86_64/xapic_state_test
+TEST_GEN_PROGS_x86_64 += x86_64/xcr0_cpuid_test
TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test
TEST_GEN_PROGS_x86_64 += x86_64/debug_regs
TEST_GEN_PROGS_x86_64 += x86_64/tsc_msrs_test
diff --git a/tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c b/tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c
new file mode 100644
index 0000000000000..6bef362872154
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * XCR0 cpuid test
+ *
+ * Copyright (C) 2022, Google LLC.
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+
+#include "kvm_util.h"
+#include "processor.h"
+
+static uint64_t get_supported_user_xfeatures(void)
+{
+ uint32_t a, b, c, d;
+
+ cpuid(0xd, &a, &b, &c, &d);
+
+ return a | ((uint64_t)d << 32);
+}
+
+static void guest_code(void)
+{
+ uint64_t xcr0_rest;
+ uint64_t supported_xcr0;
+ uint64_t xfeature_mask;
+ uint64_t supported_state;
+
+ set_cr4(get_cr4() | X86_CR4_OSXSAVE);
+
+ xcr0_rest = xgetbv(0);
+ supported_xcr0 = get_supported_user_xfeatures();
+
+ GUEST_ASSERT(xcr0_rest == 1ul);
+
+ /* Check AVX */
+ xfeature_mask = XFEATURE_MASK_SSE | XFEATURE_MASK_YMM;
+ supported_state = supported_xcr0 & xfeature_mask;
+ GUEST_ASSERT(supported_state != XFEATURE_MASK_YMM);
+
+ /* Check MPX */
+ xfeature_mask = XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR;
+ supported_state = supported_xcr0 & xfeature_mask;
+ GUEST_ASSERT((supported_state == xfeature_mask) ||
+ (supported_state == 0ul));
+
+ /* Check AVX-512 */
+ xfeature_mask = XFEATURE_MASK_SSE | XFEATURE_MASK_YMM |
+ XFEATURE_MASK_AVX512;
+ supported_state = supported_xcr0 & xfeature_mask;
+ GUEST_ASSERT((supported_state == xfeature_mask) ||
+ ((supported_state & XFEATURE_MASK_AVX512) == 0ul));
+
+ /* Check AMX */
+ xfeature_mask = XFEATURE_MASK_XTILE;
+ supported_state = supported_xcr0 & xfeature_mask;
+ GUEST_ASSERT((supported_state == xfeature_mask) ||
+ (supported_state == 0ul));
+
+ GUEST_SYNC(0);
+
+ xsetbv(0, supported_xcr0);
+
+ GUEST_DONE();
+}
+
+static void guest_gp_handler(struct ex_regs *regs)
+{
+ GUEST_ASSERT(!"Failed to set the supported xfeature bits in XCR0.");
+}
+
+int main(int argc, char *argv[])
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_run *run;
+ struct kvm_vm *vm;
+ struct ucall uc;
+
+ TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_XSAVE));
+
+ /* Tell stdout not to buffer its content */
+ setbuf(stdout, NULL);
+
+ vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+ run = vcpu->run;
+
+ vm_init_descriptor_tables(vm);
+ vcpu_init_descriptor_tables(vcpu);
+
+ while (1) {
+ vcpu_run(vcpu);
+
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Unexpected exit reason: %u (%s),\n",
+ run->exit_reason,
+ exit_reason_str(run->exit_reason));
+
+ switch (get_ucall(vcpu, &uc)) {
+ case UCALL_SYNC:
+ vm_install_exception_handler(vm, GP_VECTOR,
+ guest_gp_handler);
+ break;
+ case UCALL_ABORT:
+ REPORT_GUEST_ASSERT(uc);
+ break;
+ case UCALL_DONE:
+ goto done;
+ default:
+ TEST_FAIL("Unknown ucall %lu", uc.cmd);
+ }
+ }
+
+done:
+ kvm_vm_free(vm);
+ return 0;
+}
--
2.39.0.314.g84b9a713c41-goog
