1 files changed, 146 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86/nested_emulation_test.c b/tools/testing/selftests/kvm/x86/nested_emulation_test.c
new file mode 100644
index 000000000000..abc824dba04f
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/nested_emulation_test.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+#include "vmx.h"
+#include "svm_util.h"
+
+enum {
+	SVM_F,
+	VMX_F,
+	NR_VIRTUALIZATION_FLAVORS,
+};
+
+struct emulated_instruction {
+	const char name[32];
+	uint8_t opcode[15];
+	uint32_t exit_reason[NR_VIRTUALIZATION_FLAVORS];
+};
+
+static struct emulated_instruction instructions[] = {
+	{
+		.name = "pause",
+		.opcode = { 0xf3, 0x90 },
+		.exit_reason = { SVM_EXIT_PAUSE,
+				 EXIT_REASON_PAUSE_INSTRUCTION, }
+	},
+	{
+		.name = "hlt",
+		.opcode = { 0xf4 },
+		.exit_reason = { SVM_EXIT_HLT,
+				 EXIT_REASON_HLT, }
+	},
+};
+
+static uint8_t kvm_fep[] = { 0x0f, 0x0b, 0x6b, 0x76, 0x6d };	/* ud2 ; .ascii "kvm" */
+static uint8_t l2_guest_code[sizeof(kvm_fep) + 15];
+static uint8_t *l2_instruction = &l2_guest_code[sizeof(kvm_fep)];
+
+static uint32_t get_instruction_length(struct emulated_instruction *insn)
+{
+	uint32_t i;
+
+	for (i = 0; i < ARRAY_SIZE(insn->opcode) && insn->opcode[i]; i++)
+		;
+
+	return i;
+}
+
+static void guest_code(void *test_data)
+{
+	int f = this_cpu_has(X86_FEATURE_SVM) ? SVM_F : VMX_F;
+	int i;
+
+	memcpy(l2_guest_code, kvm_fep, sizeof(kvm_fep));
+
+	if (f == SVM_F) {
+		struct svm_test_data *svm = test_data;
+		struct vmcb *vmcb = svm->vmcb;
+
+		generic_svm_setup(svm, NULL, NULL);
+		vmcb->save.idtr.limit = 0;
+		vmcb->save.rip = (u64)l2_guest_code;
+
+		vmcb->control.intercept |= BIT_ULL(INTERCEPT_SHUTDOWN) |
+					   BIT_ULL(INTERCEPT_PAUSE) |
+					   BIT_ULL(INTERCEPT_HLT);
+		vmcb->control.intercept_exceptions = 0;
+	} else {
+		GUEST_ASSERT(prepare_for_vmx_operation(test_data));
+		GUEST_ASSERT(load_vmcs(test_data));
+
+		prepare_vmcs(test_data, NULL, NULL);
+		GUEST_ASSERT(!vmwrite(GUEST_IDTR_LIMIT, 0));
+		GUEST_ASSERT(!vmwrite(GUEST_RIP, (u64)l2_guest_code));
+		GUEST_ASSERT(!vmwrite(EXCEPTION_BITMAP, 0));
+
+		vmwrite(CPU_BASED_VM_EXEC_CONTROL, vmreadz(CPU_BASED_VM_EXEC_CONTROL) |
+						   CPU_BASED_PAUSE_EXITING |
+						   CPU_BASED_HLT_EXITING);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(instructions); i++) {
+		struct emulated_instruction *insn = &instructions[i];
+		uint32_t insn_len = get_instruction_length(insn);
+		uint32_t exit_insn_len;
+		u32 exit_reason;
+
+		/*
+		 * Copy the target instruction to the L2 code stream, and fill
+		 * the remaining bytes with INT3s so that a missed intercept
+		 * results in a consistent failure mode (SHUTDOWN).
+		 */
+		memcpy(l2_instruction, insn->opcode, insn_len);
+		memset(l2_instruction + insn_len, 0xcc, sizeof(insn->opcode) - insn_len);
+
+		if (f == SVM_F) {
+			struct svm_test_data *svm = test_data;
+			struct vmcb *vmcb = svm->vmcb;
+
+			run_guest(vmcb, svm->vmcb_gpa);
+			exit_reason = vmcb->control.exit_code;
+			exit_insn_len = vmcb->control.next_rip - vmcb->save.rip;
+			GUEST_ASSERT_EQ(vmcb->save.rip, (u64)l2_instruction);
+		} else {
+			GUEST_ASSERT_EQ(i ? vmresume() : vmlaunch(), 0);
+			exit_reason = vmreadz(VM_EXIT_REASON);
+			exit_insn_len = vmreadz(VM_EXIT_INSTRUCTION_LEN);
+			GUEST_ASSERT_EQ(vmreadz(GUEST_RIP), (u64)l2_instruction);
+		}
+
+		__GUEST_ASSERT(exit_reason == insn->exit_reason[f],
+			       "Wanted exit_reason '0x%x' for '%s', got '0x%x'",
+			       insn->exit_reason[f], insn->name, exit_reason);
+
+		__GUEST_ASSERT(exit_insn_len == insn_len,
+			       "Wanted insn_len '%u' for '%s', got '%u'",
+			       insn_len, insn->name, exit_insn_len);
+	}
+
+	GUEST_DONE();
+}
+
+int main(int argc, char *argv[])
+{
+	vm_vaddr_t nested_test_data_gva;
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+
+	TEST_REQUIRE(is_forced_emulation_enabled);
+	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SVM) || kvm_cpu_has(X86_FEATURE_VMX));
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+	vm_enable_cap(vm, KVM_CAP_EXCEPTION_PAYLOAD, -2ul);
+
+	if (kvm_cpu_has(X86_FEATURE_SVM))
+		vcpu_alloc_svm(vm, &nested_test_data_gva);
+	else
+		vcpu_alloc_vmx(vm, &nested_test_data_gva);
+
+	vcpu_args_set(vcpu, 1, nested_test_data_gva);
+
+	vcpu_run(vcpu);
+	TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE);
+
+	kvm_vm_free(vm);
+}