Commit dec79eab authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: selftests: Rework platform_info_test to actually verify #GP 

Rework platform_info_test to actually handle and verify the expected #GP
on RDMSR when the associated KVM capability is disabled.  Currently, the
test _deliberately_ doesn't handle the #GP, and instead lets it escalated
to a triple fault shutdown.

In addition to verifying that KVM generates the correct fault, handling
the #GP will be necessary (without even more shenanigans) when a future
change to the core KVM selftests library configures the IDT and exception
handlers by default (the test subtly relies on the IDT limit being '0').

Link: https://lore.kernel.org/r/20240314232637.2538648-7-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 53635ec2

tools/testing/selftests/kvm/x86_64/platform_info_test.c

+33 −33
Original line number Diff line number Diff line
@@ -24,27 +24,48 @@ 
static void guest_code(void)

{

	uint64_t msr_platform_info;

	uint8_t vector;



	for (;;) {

	GUEST_SYNC(true);

	msr_platform_info = rdmsr(MSR_PLATFORM_INFO);

	GUEST_ASSERT_EQ(msr_platform_info & MSR_PLATFORM_INFO_MAX_TURBO_RATIO,

			MSR_PLATFORM_INFO_MAX_TURBO_RATIO);

		GUEST_SYNC(0);

		asm volatile ("inc %r11");

	}



	GUEST_SYNC(false);

	vector = rdmsr_safe(MSR_PLATFORM_INFO, &msr_platform_info);

	GUEST_ASSERT_EQ(vector, GP_VECTOR);



	GUEST_DONE();

}



static void test_msr_platform_info_enabled(struct kvm_vcpu *vcpu)

int main(int argc, char *argv[])

{

	struct kvm_vcpu *vcpu;

	struct kvm_vm *vm;

	uint64_t msr_platform_info;

	struct ucall uc;



	vm_enable_cap(vcpu->vm, KVM_CAP_MSR_PLATFORM_INFO, true);

	TEST_REQUIRE(kvm_has_cap(KVM_CAP_MSR_PLATFORM_INFO));



	vm = vm_create_with_one_vcpu(&vcpu, guest_code);



	vm_init_descriptor_tables(vm);

	vcpu_init_descriptor_tables(vcpu);



	msr_platform_info = vcpu_get_msr(vcpu, MSR_PLATFORM_INFO);

	vcpu_set_msr(vcpu, MSR_PLATFORM_INFO,

		     msr_platform_info | MSR_PLATFORM_INFO_MAX_TURBO_RATIO);



	for (;;) {

		vcpu_run(vcpu);

		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);



		switch (get_ucall(vcpu, &uc)) {

		case UCALL_SYNC:

			vm_enable_cap(vm, KVM_CAP_MSR_PLATFORM_INFO, uc.args[1]);

			break;

		case UCALL_DONE:

			goto done;

		case UCALL_ABORT:

			REPORT_GUEST_ASSERT(uc);

		default:
@@ -53,28 +74,7 @@ static void test_msr_platform_info_enabled(struct kvm_vcpu *vcpu) 
		}

	}



static void test_msr_platform_info_disabled(struct kvm_vcpu *vcpu)

{

	vm_enable_cap(vcpu->vm, KVM_CAP_MSR_PLATFORM_INFO, false);

	vcpu_run(vcpu);

	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_SHUTDOWN);

}



int main(int argc, char *argv[])

{

	struct kvm_vcpu *vcpu;

	struct kvm_vm *vm;

	uint64_t msr_platform_info;



	TEST_REQUIRE(kvm_has_cap(KVM_CAP_MSR_PLATFORM_INFO));



	vm = vm_create_with_one_vcpu(&vcpu, guest_code);



	msr_platform_info = vcpu_get_msr(vcpu, MSR_PLATFORM_INFO);

	vcpu_set_msr(vcpu, MSR_PLATFORM_INFO,

		     msr_platform_info | MSR_PLATFORM_INFO_MAX_TURBO_RATIO);

	test_msr_platform_info_enabled(vcpu);

	test_msr_platform_info_disabled(vcpu);

done:

	vcpu_set_msr(vcpu, MSR_PLATFORM_INFO, msr_platform_info);



	kvm_vm_free(vm);