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KVM: selftests: Extend vmx_set_nested_state_test to cover SVM

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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@linux.dev>
Link: https://patch.msgid.link/20251121204803.991707-5-yosry.ahmed@linux.dev
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Yosry Ahmed
2025-11-21 20:48:03 +00:00
committed by Sean Christopherson
parent bda6ae6f29
commit ca2eccb953
2 changed files with 112 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
tools/testing/selftests/kvm/Makefile.kvm
View File

@@ -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

122
tools/testing/selftests/kvm/x86/vmx_set_nested_state_test.c → tools/testing/selftests/kvm/x86/nested_set_state_test.c
View File

@@ -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;