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Message-ID: <20240802185511.305849-10-seanjc@google.com>
Date: Fri, 2 Aug 2024 11:55:11 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Sean Christopherson <seanjc@...gle.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 9/9] KVM: selftests: Add a testcase for disabling feature MSRs
init quirk
Expand and rename the feature MSRs test to verify KVM's ABI and quirk
for initializing feature MSRs.
Exempt VM_CR{0,4}_FIXED1 from most tests as KVM intentionally takes full
control of the MSRs, e.g. to prevent L1 from running L2 with bogus CR0
and/or CR4 values.
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
tools/testing/selftests/kvm/Makefile | 2 +-
.../selftests/kvm/x86_64/feature_msrs_test.c | 113 ++++++++++++++++++
.../kvm/x86_64/get_msr_index_features.c | 35 ------
3 files changed, 114 insertions(+), 36 deletions(-)
create mode 100644 tools/testing/selftests/kvm/x86_64/feature_msrs_test.c
delete mode 100644 tools/testing/selftests/kvm/x86_64/get_msr_index_features.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index b084ba2262a0..827b523a18fa 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -67,7 +67,7 @@ TEST_PROGS_x86_64 += x86_64/nx_huge_pages_test.sh
TEST_GEN_PROGS_x86_64 = x86_64/cpuid_test
TEST_GEN_PROGS_x86_64 += x86_64/cr4_cpuid_sync_test
TEST_GEN_PROGS_x86_64 += x86_64/dirty_log_page_splitting_test
-TEST_GEN_PROGS_x86_64 += x86_64/get_msr_index_features
+TEST_GEN_PROGS_x86_64 += x86_64/feature_msrs_test
TEST_GEN_PROGS_x86_64 += x86_64/exit_on_emulation_failure_test
TEST_GEN_PROGS_x86_64 += x86_64/fix_hypercall_test
TEST_GEN_PROGS_x86_64 += x86_64/hwcr_msr_test
diff --git a/tools/testing/selftests/kvm/x86_64/feature_msrs_test.c b/tools/testing/selftests/kvm/x86_64/feature_msrs_test.c
new file mode 100644
index 000000000000..a72f13ae2edb
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/feature_msrs_test.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020, Red Hat, Inc.
+ */
+#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 bool is_kvm_controlled_msr(uint32_t msr)
+{
+ return msr == MSR_IA32_VMX_CR0_FIXED1 || msr == MSR_IA32_VMX_CR4_FIXED1;
+}
+
+/*
+ * For VMX MSRs with a "true" variant, KVM requires userspace to set the "true"
+ * MSR, and doesn't allow setting the hidden version.
+ */
+static bool is_hidden_vmx_msr(uint32_t msr)
+{
+ switch (msr) {
+ case MSR_IA32_VMX_PINBASED_CTLS:
+ case MSR_IA32_VMX_PROCBASED_CTLS:
+ case MSR_IA32_VMX_EXIT_CTLS:
+ case MSR_IA32_VMX_ENTRY_CTLS:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static bool is_quirked_msr(uint32_t msr)
+{
+ return msr != MSR_AMD64_DE_CFG;
+}
+
+static void test_feature_msr(uint32_t msr)
+{
+ const uint64_t supported_mask = kvm_get_feature_msr(msr);
+ uint64_t reset_value = is_quirked_msr(msr) ? supported_mask : 0;
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm;
+
+ /*
+ * Don't bother testing KVM-controlled MSRs beyond verifying that the
+ * MSR can be read from userspace. Any value is effectively legal, as
+ * KVM is bound by x86 architecture, not by ABI.
+ */
+ if (is_kvm_controlled_msr(msr))
+ return;
+
+ /*
+ * More goofy behavior. KVM reports the host CPU's actual revision ID,
+ * but initializes the vCPU's revision ID to an arbitrary value.
+ */
+ if (msr == MSR_IA32_UCODE_REV)
+ reset_value = host_cpu_is_intel ? 0x100000000ULL : 0x01000065;
+
+ /*
+ * For quirked MSRs, KVM's ABI is to initialize the vCPU's value to the
+ * full set of features supported by KVM. For non-quirked MSRs, and
+ * when the quirk is disabled, KVM must zero-initialize the MSR and let
+ * userspace do the configuration.
+ */
+ vm = vm_create_with_one_vcpu(&vcpu, NULL);
+ TEST_ASSERT(vcpu_get_msr(vcpu, msr) == reset_value,
+ "Wanted 0x%lx for %squirked MSR 0x%x, got 0x%lx",
+ reset_value, is_quirked_msr(msr) ? "" : "non-", msr,
+ vcpu_get_msr(vcpu, msr));
+ if (!is_hidden_vmx_msr(msr))
+ vcpu_set_msr(vcpu, msr, supported_mask);
+ kvm_vm_free(vm);
+
+ if (is_hidden_vmx_msr(msr))
+ return;
+
+ if (!kvm_has_cap(KVM_CAP_DISABLE_QUIRKS2) ||
+ !(kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) & KVM_X86_QUIRK_STUFF_FEATURE_MSRS))
+ return;
+
+ vm = vm_create(1);
+ vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, KVM_X86_QUIRK_STUFF_FEATURE_MSRS);
+
+ vcpu = vm_vcpu_add(vm, 0, NULL);
+ TEST_ASSERT(!vcpu_get_msr(vcpu, msr),
+ "Quirk disabled, wanted '0' for MSR 0x%x, got 0x%lx",
+ msr, vcpu_get_msr(vcpu, msr));
+ kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+ const struct kvm_msr_list *feature_list;
+ int i;
+
+ /*
+ * Skip the entire test if MSR_FEATURES isn't supported, other tests
+ * will cover the "regular" list of MSRs, the coverage here is purely
+ * opportunistic and not interesting on its own.
+ */
+ TEST_REQUIRE(kvm_has_cap(KVM_CAP_GET_MSR_FEATURES));
+
+ (void)kvm_get_msr_index_list();
+
+ feature_list = kvm_get_feature_msr_index_list();
+ for (i = 0; i < feature_list->nmsrs; i++)
+ test_feature_msr(feature_list->indices[i]);
+}
diff --git a/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c b/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c
deleted file mode 100644
index d09b3cbcadc6..000000000000
--- a/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c
+++ /dev/null
@@ -1,35 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Test that KVM_GET_MSR_INDEX_LIST and
- * KVM_GET_MSR_FEATURE_INDEX_LIST work as intended
- *
- * Copyright (C) 2020, Red Hat, Inc.
- */
-#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"
-
-int main(int argc, char *argv[])
-{
- const struct kvm_msr_list *feature_list;
- int i;
-
- /*
- * Skip the entire test if MSR_FEATURES isn't supported, other tests
- * will cover the "regular" list of MSRs, the coverage here is purely
- * opportunistic and not interesting on its own.
- */
- TEST_REQUIRE(kvm_has_cap(KVM_CAP_GET_MSR_FEATURES));
-
- (void)kvm_get_msr_index_list();
-
- feature_list = kvm_get_feature_msr_index_list();
- for (i = 0; i < feature_list->nmsrs; i++)
- kvm_get_feature_msr(feature_list->indices[i]);
-}
--
2.46.0.rc2.264.g509ed76dc8-goog
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