Commit a323845d authored by David Matlack's avatar David Matlack Committed by Sean Christopherson
Browse files

KVM: selftests: Expect #PF(RSVD) when TDP is disabled 



Change smaller_maxphyaddr_emulation_test to expect a #PF(RSVD), rather
than an emulation failure, when TDP is disabled. KVM only needs to
emulate instructions to emulate a smaller guest.MAXPHYADDR when TDP is
enabled.

Fixes: 39bbcc3a ("selftests: kvm: Allows userspace to handle emulation errors.")
Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-10-dmatlack@google.com


[sean: massage comment to talk about having to emulate due to MAXPHYADDR]
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent b9635930

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

+46 −5
Original line number Diff line number Diff line
@@ -21,9 +21,27 @@ 
#define MEM_REGION_SLOT	10

#define MEM_REGION_SIZE PAGE_SIZE



static void guest_code(void)

static void guest_code(bool tdp_enabled)

{

	flds(MEM_REGION_GVA);

	uint64_t error_code;

	uint64_t vector;



	vector = kvm_asm_safe_ec(FLDS_MEM_EAX, error_code, "a"(MEM_REGION_GVA));



	/*

	 * When TDP is enabled, flds will trigger an emulation failure, exit to

	 * userspace, and then the selftest host "VMM" skips the instruction.

	 *

	 * When TDP is disabled, no instruction emulation is required so flds

	 * should generate #PF(RSVD).

	 */

	if (tdp_enabled) {

		GUEST_ASSERT(!vector);

	} else {

		GUEST_ASSERT_EQ(vector, PF_VECTOR);

		GUEST_ASSERT(error_code & PFERR_RSVD_MASK);

	}



	GUEST_DONE();

}
@@ -31,6 +49,7 @@ int main(int argc, char *argv[]) 
{

	struct kvm_vcpu *vcpu;

	struct kvm_vm *vm;

	struct ucall uc;

	uint64_t *pte;

	uint64_t *hva;

	uint64_t gpa;
@@ -39,6 +58,10 @@ int main(int argc, char *argv[]) 
	TEST_REQUIRE(kvm_has_cap(KVM_CAP_SMALLER_MAXPHYADDR));



	vm = vm_create_with_one_vcpu(&vcpu, guest_code);

	vcpu_args_set(vcpu, 1, kvm_is_tdp_enabled());



	vm_init_descriptor_tables(vm);

	vcpu_init_descriptor_tables(vcpu);



	vcpu_set_cpuid_maxphyaddr(vcpu, MAXPHYADDR);
@@ -60,9 +83,27 @@ int main(int argc, char *argv[]) 
	*pte |= BIT_ULL(MAXPHYADDR);



	vcpu_run(vcpu);



	/*

	 * When TDP is enabled, KVM must emulate in response the guest physical

	 * address that is illegal from the guest's perspective, but is legal

	 * from hardware's perspeective.  This should result in an emulation

	 * failure exit to userspace since KVM doesn't support emulating flds.

	 */

	if (kvm_is_tdp_enabled()) {

		handle_flds_emulation_failure_exit(vcpu);

		vcpu_run(vcpu);

	ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE);

	}



	switch (get_ucall(vcpu, &uc)) {

	case UCALL_ABORT:

		REPORT_GUEST_ASSERT(uc);

		break;

	case UCALL_DONE:

		break;

	default:

		TEST_FAIL("Unrecognized ucall: %lu\n", uc.cmd);

	}



	kvm_vm_free(vm);