[PATCH 3/4] selftests: KVM: Add test for "load IA32_PERF_GLOBAL_CTRL" invariance

[Oliver Upton <oupton@google.com>]

Assert that clearing the "load IA32_PERF_GLOBAL_CTRL" VM-{Entry,Exit}
capability bits is preserved across KVM_SET_CPUID2.

Signed-off-by: Oliver Upton <oupton@google.com>
---
 tools/testing/selftests/kvm/.gitignore        |  1 +
 tools/testing/selftests/kvm/Makefile          |  1 +
 .../kvm/x86_64/vmx_capability_msrs_test.c     | 82 +++++++++++++++++++
 3 files changed, 84 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86_64/vmx_capability_msrs_test.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index dce7de7755e6..d1e6757aed2f 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -36,6 +36,7 @@
 /x86_64/userspace_io_test
 /x86_64/userspace_msr_exit_test
 /x86_64/vmx_apic_access_test
+/x86_64/vmx_capability_msrs_test
 /x86_64/vmx_close_while_nested_test
 /x86_64/vmx_dirty_log_test
 /x86_64/vmx_exception_with_invalid_guest_state
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 0e4926bc9a58..083c437a852f 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -68,6 +68,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/sync_regs_test
 TEST_GEN_PROGS_x86_64 += x86_64/userspace_io_test
 TEST_GEN_PROGS_x86_64 += x86_64/userspace_msr_exit_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_apic_access_test
+TEST_GEN_PROGS_x86_64 += x86_64/vmx_capability_msrs_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_close_while_nested_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_dirty_log_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_exception_with_invalid_guest_state
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_capability_msrs_test.c b/tools/testing/selftests/kvm/x86_64/vmx_capability_msrs_test.c
new file mode 100644
index 000000000000..8a1a545e658b
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/vmx_capability_msrs_test.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * VMX capability MSRs test
+ *
+ * Copyright (C) 2022 Google LLC
+ *
+ * Regression tests to check that updates to guest CPUID do not affect the
+ * values of VMX capability MSRs.
+ */
+
+#include "kvm_util.h"
+#include "vmx.h"
+
+#define VCPU_ID 0
+
+static void get_vmx_capability_msr(struct kvm_vm *vm, uint32_t msr_index,
+				   uint32_t *low, uint32_t *high)
+{
+	uint64_t val;
+
+	val = vcpu_get_msr(vm, VCPU_ID, msr_index);
+	*low = val;
+	*high = val >> 32;
+}
+
+static void set_vmx_capability_msr(struct kvm_vm *vm, uint32_t msr_index,
+				   uint32_t low, uint32_t high)
+{
+	uint64_t val = (((uint64_t) high) << 32) | low;
+
+	vcpu_set_msr(vm, VCPU_ID, msr_index, val);
+}
+
+/*
+ * Test to assert that clearing the "load IA32_PERF_GLOBAL_CTRL" VM-{Entry,Exit}
+ * control capability bits is preserved across a KVM_SET_CPUID2.
+ */
+static void load_perf_global_ctrl_test(struct kvm_vm *vm)
+{
+	uint32_t entry_low, entry_high, exit_low, exit_high;
+	struct kvm_cpuid2 *cpuid;
+
+	get_vmx_capability_msr(vm, MSR_IA32_VMX_TRUE_ENTRY_CTLS, &entry_low, &entry_high);
+	get_vmx_capability_msr(vm, MSR_IA32_VMX_TRUE_EXIT_CTLS, &exit_low, &exit_high);
+
+	if (!(entry_high & VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL) ||
+	    !(exit_high & VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL)) {
+		print_skip("\"load IA32_PERF_GLOBAL_CTRL\" VM-{Entry,Exit} control not supported");
+		return;
+	}
+
+	entry_high &= ~VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL;
+	exit_high &= ~VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL;
+
+	set_vmx_capability_msr(vm, MSR_IA32_VMX_TRUE_ENTRY_CTLS, entry_low, entry_high);
+	set_vmx_capability_msr(vm, MSR_IA32_VMX_TRUE_EXIT_CTLS, exit_low, exit_high);
+
+	cpuid = kvm_get_supported_cpuid();
+	vcpu_set_cpuid(vm, VCPU_ID, cpuid);
+
+	get_vmx_capability_msr(vm, MSR_IA32_VMX_TRUE_ENTRY_CTLS, &entry_low, &entry_high);
+	get_vmx_capability_msr(vm, MSR_IA32_VMX_TRUE_EXIT_CTLS, &exit_low, &exit_high);
+
+	TEST_ASSERT(!(entry_high & VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL),
+		    "\"load IA32_PERF_GLOBAL_CTRL\" VM-Entry bit set");
+	TEST_ASSERT(!(exit_high & VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL),
+		    "\"load IA32_PERF_GLOBAL_CTRL\" VM-Exit bit set");
+}
+
+int main(void)
+{
+	struct kvm_vm *vm;
+
+	nested_vmx_check_supported();
+
+	/* No need to run a guest for these tests */
+	vm = vm_create_default(VCPU_ID, 0, NULL);
+
+	load_perf_global_ctrl_test(vm);
+
+	kvm_vm_free(vm);
+}
-- 
2.35.0.rc2.247.g8bbb082509-goog