[PATCH v3 5/6] selftests: KVM: Add test for PERF_GLOBAL_CTRL VMX control MSR bits

[Oliver Upton <oupton@google.com>]

Test that the default behavior of KVM is to ignore userspace MSR writes
and conditionally expose the "load IA32_PERF_GLOBAL_CTRL" bits in the
VMX control MSRs if the guest CPUID exposes a supporting vPMU.
Additionally, test that when the corresponding quirk is disabled,
userspace can still clear these bits regardless of what is exposed in
CPUID.

Signed-off-by: Oliver Upton <oupton@google.com>
---
 tools/testing/selftests/kvm/.gitignore        |   1 +
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../kvm/x86_64/vmx_control_msrs_test.c        | 145 ++++++++++++++++++
 3 files changed, 147 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86_64/vmx_control_msrs_test.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index dce7de7755e6..044aef3a8574 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_close_while_nested_test
+/x86_64/vmx_control_msrs_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 17c3f0749f05..2d5e1029ee2d 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_close_while_nested_test
+TEST_GEN_PROGS_x86_64 += x86_64/vmx_control_msrs_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_control_msrs_test.c b/tools/testing/selftests/kvm/x86_64/vmx_control_msrs_test.c
new file mode 100644
index 000000000000..ab598d9e7582
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/vmx_control_msrs_test.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * VMX control MSR test
+ *
+ * Copyright (C) 2022 Google LLC.
+ *
+ * Tests for KVM ownership of bits in the VMX entry/exit control MSRs. Checks
+ * that KVM will set owned bits where appropriate, and will not if
+ * KVM_X86_QUIRK_TWEAK_VMX_CTRL_MSRS is disabled.
+ */
+
+#include "kvm_util.h"
+#include "vmx.h"
+
+#define VCPU_ID 0
+
+static void get_vmx_control_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_control_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);
+}
+
+static void test_vmx_control_msr(struct kvm_vm *vm, uint32_t msr_index, uint32_t set,
+				 uint32_t clear, uint32_t exp_set, uint32_t exp_clear)
+{
+	uint32_t low, high;
+
+	get_vmx_control_msr(vm, msr_index, &low, &high);
+
+	high &= ~clear;
+	high |= set;
+
+	set_vmx_control_msr(vm, msr_index, low, high);
+
+	get_vmx_control_msr(vm, msr_index, &low, &high);
+	ASSERT_EQ(high & exp_set, exp_set);
+	ASSERT_EQ(~high & exp_clear, exp_clear);
+}
+
+static void clear_performance_monitoring_leaf(struct kvm_cpuid2 *cpuid)
+{
+	struct kvm_cpuid_entry2 ent = {0};
+
+	ent.function = 0xa;
+	TEST_ASSERT(set_cpuid(cpuid, &ent),
+		    "failed to clear Architectual Performance Monitoring leaf (0xA)");
+}
+
+static void load_perf_global_ctrl_test(struct kvm_vm *vm)
+{
+	uint32_t entry_low, entry_high, exit_low, exit_high;
+	struct kvm_enable_cap cap = {0};
+	struct kvm_cpuid2 *cpuid;
+
+	get_vmx_control_msr(vm, MSR_IA32_VMX_TRUE_ENTRY_CTLS, &entry_low, &entry_high);
+	get_vmx_control_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} controls not supported");
+		return;
+	}
+
+	/*
+	 * Test that KVM will set these bits regardless of userspace if the
+	 * guest CPUID exposes a supporting vPMU.
+	 */
+	test_vmx_control_msr(vm, MSR_IA32_VMX_TRUE_ENTRY_CTLS, 0,
+			     VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL,
+			     VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL,
+			     0);
+	test_vmx_control_msr(vm, MSR_IA32_VMX_TRUE_EXIT_CTLS, 0,
+			     VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL,
+			     VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL,
+			     0);
+
+	/*
+	 * Hide vPMU in CPUID
+	 */
+	cpuid = _kvm_get_supported_cpuid();
+	clear_performance_monitoring_leaf(cpuid);
+	vcpu_set_cpuid(vm, VCPU_ID, cpuid);
+	free(cpuid);
+
+	/*
+	 * Test that KVM will clear these bits if guest CPUID does not expose a
+	 * supporting vPMU.
+	 */
+	test_vmx_control_msr(vm, MSR_IA32_VMX_TRUE_ENTRY_CTLS, 0, 0, 0,
+			     VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL);
+	test_vmx_control_msr(vm, MSR_IA32_VMX_TRUE_EXIT_CTLS, 0, 0, 0,
+			     VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL);
+
+	/*
+	 * Re-enable vPMU in CPUID
+	 */
+	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
+
+	/*
+	 * Disable the quirk, giving userspace control of the VMX capability
+	 * MSRs.
+	 */
+	cap.cap = KVM_CAP_DISABLE_QUIRKS;
+	cap.args[0] = KVM_X86_QUIRK_TWEAK_VMX_CTRL_MSRS;
+	vm_enable_cap(vm, &cap);
+
+	/*
+	 * Test that userspace can clear these bits, even if it exposes a vPMU
+	 * that supports IA32_PERF_GLOBAL_CTRL.
+	 */
+	test_vmx_control_msr(vm, MSR_IA32_VMX_TRUE_ENTRY_CTLS, 0,
+			     VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL,
+			     0,
+			     VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL);
+	test_vmx_control_msr(vm, MSR_IA32_VMX_TRUE_EXIT_CTLS, 0,
+			     VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL,
+			     0,
+			     VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL);
+}
+
+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);
+}
-- 
2.35.1.574.g5d30c73bfb-goog