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Message-ID: <20251121204803.991707-5-yosry.ahmed@linux.dev>
Date: Fri, 21 Nov 2025 20:48:03 +0000
From: Yosry Ahmed <yosry.ahmed@...ux.dev>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <seanjc@...gle.com>,
Jim Mattson <jmattson@...gle.com>,
kvm@...r.kernel.org,
linux-kernel@...r.kernel.org,
Yosry Ahmed <yosry.ahmed@...ux.dev>
Subject: [PATCH v3 4/4] KVM: selftests: Extend vmx_set_nested_state_test to cover SVM
Add test cases for the validation checks in svm_set_nested_state(), and
allow the test to run with SVM as well as VMX. The SVM test also makes
sure that KVM_SET_NESTED_STATE accepts GIF being set or cleared if
EFER.SVME is cleared, verifying a recently fixed bug where GIF was
incorrectly expected to always be set when EFER.SVME is cleared.
Signed-off-by: Yosry Ahmed <yosry.ahmed@...ux.dev>
---
tools/testing/selftests/kvm/Makefile.kvm | 2 +-
...d_state_test.c => nested_set_state_test.c} | 122 ++++++++++++++++--
2 files changed, 112 insertions(+), 12 deletions(-)
rename tools/testing/selftests/kvm/x86/{vmx_set_nested_state_test.c => nested_set_state_test.c} (71%)
diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 7ebf30a87a2b..7567c936202f 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -92,6 +92,7 @@ TEST_GEN_PROGS_x86 += x86/nested_close_kvm_test
TEST_GEN_PROGS_x86 += x86/nested_emulation_test
TEST_GEN_PROGS_x86 += x86/nested_exceptions_test
TEST_GEN_PROGS_x86 += x86/nested_invalid_cr3_test
+TEST_GEN_PROGS_x86 += x86/nested_set_state_test
TEST_GEN_PROGS_x86 += x86/nested_tsc_adjust_test
TEST_GEN_PROGS_x86 += x86/nested_tsc_scaling_test
TEST_GEN_PROGS_x86 += x86/platform_info_test
@@ -120,7 +121,6 @@ TEST_GEN_PROGS_x86 += x86/vmx_exception_with_invalid_guest_state
TEST_GEN_PROGS_x86 += x86/vmx_msrs_test
TEST_GEN_PROGS_x86 += x86/vmx_invalid_nested_guest_state
TEST_GEN_PROGS_x86 += x86/vmx_nested_la57_state_test
-TEST_GEN_PROGS_x86 += x86/vmx_set_nested_state_test
TEST_GEN_PROGS_x86 += x86/apic_bus_clock_test
TEST_GEN_PROGS_x86 += x86/xapic_ipi_test
TEST_GEN_PROGS_x86 += x86/xapic_state_test
diff --git a/tools/testing/selftests/kvm/x86/vmx_set_nested_state_test.c b/tools/testing/selftests/kvm/x86/nested_set_state_test.c
similarity index 71%
rename from tools/testing/selftests/kvm/x86/vmx_set_nested_state_test.c
rename to tools/testing/selftests/kvm/x86/nested_set_state_test.c
index b59a8a17084d..0f2102b43629 100644
--- a/tools/testing/selftests/kvm/x86/vmx_set_nested_state_test.c
+++ b/tools/testing/selftests/kvm/x86/nested_set_state_test.c
@@ -1,7 +1,5 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * vmx_set_nested_state_test
- *
* Copyright (C) 2019, Google LLC.
*
* This test verifies the integrity of calling the ioctl KVM_SET_NESTED_STATE.
@@ -11,6 +9,7 @@
#include "kvm_util.h"
#include "processor.h"
#include "vmx.h"
+#include "svm_util.h"
#include <errno.h>
#include <linux/kvm.h>
@@ -249,6 +248,104 @@ void test_vmx_nested_state(struct kvm_vcpu *vcpu)
free(state);
}
+static void vcpu_efer_enable_svm(struct kvm_vcpu *vcpu)
+{
+ uint64_t old_efer = vcpu_get_msr(vcpu, MSR_EFER);
+
+ vcpu_set_msr(vcpu, MSR_EFER, old_efer | EFER_SVME);
+}
+
+static void vcpu_efer_disable_svm(struct kvm_vcpu *vcpu)
+{
+ uint64_t old_efer = vcpu_get_msr(vcpu, MSR_EFER);
+
+ vcpu_set_msr(vcpu, MSR_EFER, old_efer & ~EFER_SVME);
+}
+
+void set_default_svm_state(struct kvm_nested_state *state, int size)
+{
+ memset(state, 0, size);
+ state->format = 1;
+ state->size = size;
+ state->hdr.svm.vmcb_pa = 0x3000;
+}
+
+void test_svm_nested_state(struct kvm_vcpu *vcpu)
+{
+ /* Add a page for VMCB. */
+ const int state_sz = sizeof(struct kvm_nested_state) + getpagesize();
+ struct kvm_nested_state *state =
+ (struct kvm_nested_state *)malloc(state_sz);
+
+ vcpu_set_cpuid_feature(vcpu, X86_FEATURE_SVM);
+
+ /* The format must be set to 1. 0 for VMX, 1 for SVM. */
+ set_default_svm_state(state, state_sz);
+ state->format = 0;
+ test_nested_state_expect_einval(vcpu, state);
+
+ /* Invalid flags are rejected, KVM_STATE_NESTED_EVMCS is VMX-only */
+ set_default_svm_state(state, state_sz);
+ state->flags = KVM_STATE_NESTED_EVMCS;
+ test_nested_state_expect_einval(vcpu, state);
+
+ /*
+ * If EFER.SVME is clear, guest mode is disallowed and GIF can be set or
+ * cleared.
+ */
+ vcpu_efer_disable_svm(vcpu);
+
+ set_default_svm_state(state, state_sz);
+ state->flags = KVM_STATE_NESTED_GUEST_MODE;
+ test_nested_state_expect_einval(vcpu, state);
+
+ state->flags = 0;
+ test_nested_state(vcpu, state);
+
+ state->flags = KVM_STATE_NESTED_GIF_SET;
+ test_nested_state(vcpu, state);
+
+ /* Enable SVM in the guest EFER. */
+ vcpu_efer_enable_svm(vcpu);
+
+ /* Setting vmcb_pa to a non-aligned address is only fine when not entering guest mode */
+ set_default_svm_state(state, state_sz);
+ state->hdr.svm.vmcb_pa = -1ull;
+ state->flags = 0;
+ test_nested_state(vcpu, state);
+ state->flags = KVM_STATE_NESTED_GUEST_MODE;
+ test_nested_state_expect_einval(vcpu, state);
+
+ /*
+ * Size must be large enough to fit kvm_nested_state and VMCB
+ * only when entering guest mode.
+ */
+ set_default_svm_state(state, state_sz/2);
+ state->flags = 0;
+ test_nested_state(vcpu, state);
+ state->flags = KVM_STATE_NESTED_GUEST_MODE;
+ test_nested_state_expect_einval(vcpu, state);
+
+ /*
+ * Test that if we leave nesting the state reflects that when we get it
+ * again, except for vmcb_pa, which is always returned as 0 when not in
+ * guest mode.
+ */
+ set_default_svm_state(state, state_sz);
+ state->hdr.svm.vmcb_pa = -1ull;
+ state->flags = KVM_STATE_NESTED_GIF_SET;
+ test_nested_state(vcpu, state);
+ vcpu_nested_state_get(vcpu, state);
+ TEST_ASSERT(state->size >= sizeof(*state) && state->size <= state_sz,
+ "Size must be between %ld and %d. The size returned was %d.",
+ sizeof(*state), state_sz, state->size);
+
+ TEST_ASSERT_EQ(state->hdr.svm.vmcb_pa, 0);
+ TEST_ASSERT_EQ(state->flags, KVM_STATE_NESTED_GIF_SET);
+
+ free(state);
+}
+
int main(int argc, char *argv[])
{
struct kvm_vm *vm;
@@ -257,20 +354,20 @@ int main(int argc, char *argv[])
have_evmcs = kvm_check_cap(KVM_CAP_HYPERV_ENLIGHTENED_VMCS);
+ TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX) ||
+ kvm_cpu_has(X86_FEATURE_SVM));
TEST_REQUIRE(kvm_has_cap(KVM_CAP_NESTED_STATE));
- /*
- * AMD currently does not implement set_nested_state, so for now we
- * just early out.
- */
- TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
-
vm = vm_create_with_one_vcpu(&vcpu, NULL);
/*
- * First run tests with VMX disabled to check error handling.
+ * First run tests with VMX/SVM disabled to check error handling.
+ * test_{vmx/svm}_nested_state() will re-enable as needed.
*/
- vcpu_clear_cpuid_feature(vcpu, X86_FEATURE_VMX);
+ if (kvm_cpu_has(X86_FEATURE_VMX))
+ vcpu_clear_cpuid_feature(vcpu, X86_FEATURE_VMX);
+ else
+ vcpu_clear_cpuid_feature(vcpu, X86_FEATURE_SVM);
/* Passing a NULL kvm_nested_state causes a EFAULT. */
test_nested_state_expect_efault(vcpu, NULL);
@@ -299,7 +396,10 @@ int main(int argc, char *argv[])
state.flags = KVM_STATE_NESTED_RUN_PENDING;
test_nested_state_expect_einval(vcpu, &state);
- test_vmx_nested_state(vcpu);
+ if (kvm_cpu_has(X86_FEATURE_VMX))
+ test_vmx_nested_state(vcpu);
+ else
+ test_svm_nested_state(vcpu);
kvm_vm_free(vm);
return 0;
--
2.52.0.rc2.455.g230fcf2819-goog
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