1 files changed, 103 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_invalid_nested_guest_state.c b/tools/testing/selftests/kvm/x86_64/vmx_invalid_nested_guest_state.c
new file mode 100644
index 000000000000..a100ee5f0009
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/vmx_invalid_nested_guest_state.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+#include "vmx.h"
+
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "kselftest.h"
+
+#define ARBITRARY_IO_PORT 0x2000
+
+static struct kvm_vm *vm;
+
+static void l2_guest_code(void)
+{
+	/*
+	 * Generate an exit to L0 userspace, i.e. main(), via I/O to an
+	 * arbitrary port.
+	 */
+	asm volatile("inb %%dx, %%al"
+		     : : [port] "d" (ARBITRARY_IO_PORT) : "rax");
+}
+
+static void l1_guest_code(struct vmx_pages *vmx_pages)
+{
+#define L2_GUEST_STACK_SIZE 64
+	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
+
+	GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
+	GUEST_ASSERT(load_vmcs(vmx_pages));
+
+	/* Prepare the VMCS for L2 execution. */
+	prepare_vmcs(vmx_pages, l2_guest_code,
+		     &l2_guest_stack[L2_GUEST_STACK_SIZE]);
+
+	/*
+	 * L2 must be run without unrestricted guest, verify that the selftests
+	 * library hasn't enabled it.  Because KVM selftests jump directly to
+	 * 64-bit mode, unrestricted guest support isn't required.
+	 */
+	GUEST_ASSERT(!(vmreadz(CPU_BASED_VM_EXEC_CONTROL) & CPU_BASED_ACTIVATE_SECONDARY_CONTROLS) ||
+		     !(vmreadz(SECONDARY_VM_EXEC_CONTROL) & SECONDARY_EXEC_UNRESTRICTED_GUEST));
+
+	GUEST_ASSERT(!vmlaunch());
+
+	/* L2 should triple fault after main() stuffs invalid guest state. */
+	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_TRIPLE_FAULT);
+	GUEST_DONE();
+}
+
+int main(int argc, char *argv[])
+{
+	vm_vaddr_t vmx_pages_gva;
+	struct kvm_sregs sregs;
+	struct kvm_vcpu *vcpu;
+	struct kvm_run *run;
+	struct ucall uc;
+
+	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
+
+	vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
+
+	/* Allocate VMX pages and shared descriptors (vmx_pages). */
+	vcpu_alloc_vmx(vm, &vmx_pages_gva);
+	vcpu_args_set(vcpu, 1, vmx_pages_gva);
+
+	vcpu_run(vcpu);
+
+	run = vcpu->run;
+
+	/*
+	 * The first exit to L0 userspace should be an I/O access from L2.
+	 * Running L1 should launch L2 without triggering an exit to userspace.
+	 */
+	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
+
+	TEST_ASSERT(run->io.port == ARBITRARY_IO_PORT,
+		    "Expected IN from port %d from L2, got port %d",
+		    ARBITRARY_IO_PORT, run->io.port);
+
+	/*
+	 * Stuff invalid guest state for L2 by making TR unusuable.  The next
+	 * KVM_RUN should induce a TRIPLE_FAULT in L2 as KVM doesn't support
+	 * emulating invalid guest state for L2.
+	 */
+	memset(&sregs, 0, sizeof(sregs));
+	vcpu_sregs_get(vcpu, &sregs);
+	sregs.tr.unusable = 1;
+	vcpu_sregs_set(vcpu, &sregs);
+
+	vcpu_run(vcpu);
+
+	switch (get_ucall(vcpu, &uc)) {
+	case UCALL_DONE:
+		break;
+	case UCALL_ABORT:
+		REPORT_GUEST_ASSERT(uc);
+	default:
+		TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
+	}
+}