[PATCH 1/3] KVM: selftests: evmcs_test: Check that VMLAUNCH with bogus EVMPTR is causing #UD

From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] KVM: selftests: evmcs_test: Check that VMLAUNCH with bogus EVMPTR is causing #UD
Date: Wed,  5 May 2021 17:18:21 +0200	[thread overview]
Message-ID: <20210505151823.1341678-2-vkuznets@redhat.com> (raw)
In-Reply-To: <20210505151823.1341678-1-vkuznets@redhat.com>

'run->exit_reason == KVM_EXIT_SHUTDOWN' check is not ideal as we may be
getting some unexpected exception. Directly check for #UD instead.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 .../testing/selftests/kvm/x86_64/evmcs_test.c | 24 ++++++++++++-------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/evmcs_test.c b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
index ca22ee6d19cb..b01f64ac6ce3 100644
--- a/tools/testing/selftests/kvm/x86_64/evmcs_test.c
+++ b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
@@ -19,6 +19,14 @@
 
 #define VCPU_ID		5
 
+static int ud_count;
+
+static void guest_ud_handler(struct ex_regs *regs)
+{
+	ud_count++;
+	regs->rip += 3; /* VMLAUNCH */
+}
+
 void l2_guest_code(void)
 {
 	GUEST_SYNC(7);
@@ -71,11 +79,11 @@ void guest_code(struct vmx_pages *vmx_pages)
 	if (vmx_pages)
 		l1_guest_code(vmx_pages);
 
-	GUEST_DONE();
-
 	/* Try enlightened vmptrld with an incorrect GPA */
 	evmcs_vmptrld(0xdeadbeef, vmx_pages->enlightened_vmcs);
 	GUEST_ASSERT(vmlaunch());
+	GUEST_ASSERT(ud_count == 1);
+	GUEST_DONE();
 }
 
 int main(int argc, char *argv[])
@@ -109,6 +117,10 @@ int main(int argc, char *argv[])
 	vcpu_alloc_vmx(vm, &vmx_pages_gva);
 	vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
 
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(vm, VCPU_ID);
+	vm_handle_exception(vm, UD_VECTOR, guest_ud_handler);
+
 	for (stage = 1;; stage++) {
 		_vcpu_run(vm, VCPU_ID);
 		TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
@@ -124,7 +136,7 @@ int main(int argc, char *argv[])
 		case UCALL_SYNC:
 			break;
 		case UCALL_DONE:
-			goto part1_done;
+			goto done;
 		default:
 			TEST_FAIL("Unknown ucall %lu", uc.cmd);
 		}
@@ -156,10 +168,6 @@ int main(int argc, char *argv[])
 			    (ulong) regs2.rdi, (ulong) regs2.rsi);
 	}
 
-part1_done:
-	_vcpu_run(vm, VCPU_ID);
-	TEST_ASSERT(run->exit_reason == KVM_EXIT_SHUTDOWN,
-		    "Unexpected successful VMEnter with invalid eVMCS pointer!");
-
+done:
 	kvm_vm_free(vm);
 }
-- 
2.30.2

