tools/testing/selftests/kvm/x86_64/state_test.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * KVM_GET/SET_* tests
  *
  * Copyright (C) 2018, Red Hat, Inc.
  *
  * Tests for vCPU state save/restore, including nested guest state.
  */
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/ioctl.h>

 #include "test_util.h"

 #include "kvm_util.h"
 #include "processor.h"
 #include "vmx.h"
 #include "svm_util.h"

 #define L2_GUEST_STACK_SIZE 256

 void svm_l2_guest_code(void)
 {
 	GUEST_SYNC(4);
 	/* Exit to L1 */
 	vmcall();
 	GUEST_SYNC(6);
 	/* Done, exit to L1 and never come back.  */
 	vmcall();
 }

 static void svm_l1_guest_code(struct svm_test_data *svm)
 {
 	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
 	struct vmcb *vmcb = svm->vmcb;

 	GUEST_ASSERT(svm->vmcb_gpa);
 	/* Prepare for L2 execution. */
 	generic_svm_setup(svm, svm_l2_guest_code,
 			  &l2_guest_stack[L2_GUEST_STACK_SIZE]);

 	GUEST_SYNC(3);
 	run_guest(vmcb, svm->vmcb_gpa);
 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
 	GUEST_SYNC(5);
 	vmcb->save.rip += 3;
 	run_guest(vmcb, svm->vmcb_gpa);
 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
 	GUEST_SYNC(7);
 }

 void vmx_l2_guest_code(void)
 {
 	GUEST_SYNC(6);

 	/* Exit to L1 */
 	vmcall();

 	/* L1 has now set up a shadow VMCS for us.  */
 	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
 	GUEST_SYNC(10);
 	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
 	GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0fffee));
 	GUEST_SYNC(11);
 	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0fffee);
 	GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0ffffee));
 	GUEST_SYNC(12);

 	/* Done, exit to L1 and never come back.  */
 	vmcall();
 }

 static void vmx_l1_guest_code(struct vmx_pages *vmx_pages)
 {
 	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];

 	GUEST_ASSERT(vmx_pages->vmcs_gpa);
 	GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
 	GUEST_SYNC(3);
 	GUEST_ASSERT(load_vmcs(vmx_pages));
 	GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);

 	GUEST_SYNC(4);
 	GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);

 	prepare_vmcs(vmx_pages, vmx_l2_guest_code,
 		     &l2_guest_stack[L2_GUEST_STACK_SIZE]);

 	GUEST_SYNC(5);
 	GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
 	GUEST_ASSERT(!vmlaunch());
 	GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
 	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

 	/* Check that the launched state is preserved.  */
 	GUEST_ASSERT(vmlaunch());

 	GUEST_ASSERT(!vmresume());
 	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

 	GUEST_SYNC(7);
 	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

 	GUEST_ASSERT(!vmresume());
 	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

 	vmwrite(GUEST_RIP, vmreadz(GUEST_RIP) + 3);

 	vmwrite(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_SHADOW_VMCS);
 	vmwrite(VMCS_LINK_POINTER, vmx_pages->shadow_vmcs_gpa);

 	GUEST_ASSERT(!vmptrld(vmx_pages->shadow_vmcs_gpa));
 	GUEST_ASSERT(vmlaunch());
 	GUEST_SYNC(8);
 	GUEST_ASSERT(vmlaunch());
 	GUEST_ASSERT(vmresume());

 	vmwrite(GUEST_RIP, 0xc0ffee);
 	GUEST_SYNC(9);
 	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);

 	GUEST_ASSERT(!vmptrld(vmx_pages->vmcs_gpa));
 	GUEST_ASSERT(!vmresume());
 	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

 	GUEST_ASSERT(!vmptrld(vmx_pages->shadow_vmcs_gpa));
 	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffffee);
 	GUEST_ASSERT(vmlaunch());
 	GUEST_ASSERT(vmresume());
 	GUEST_SYNC(13);
 	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffffee);
 	GUEST_ASSERT(vmlaunch());
 	GUEST_ASSERT(vmresume());
 }

 static void __attribute__((__flatten__)) guest_code(void *arg)
 {
 	GUEST_SYNC(1);

 	if (this_cpu_has(X86_FEATURE_XSAVE)) {
 		uint64_t supported_xcr0 = this_cpu_supported_xcr0();
 		uint8_t buffer[4096];

 		memset(buffer, 0xcc, sizeof(buffer));

 		set_cr4(get_cr4() | X86_CR4_OSXSAVE);
 		GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));

 		xsetbv(0, xgetbv(0) | supported_xcr0);

 		/*
 		 * Modify state for all supported xfeatures to take them out of
 		 * their "init" state, i.e. to make them show up in XSTATE_BV.
 		 *
 		 * Note off-by-default features, e.g. AMX, are out of scope for
 		 * this particular testcase as they have a different ABI.
 		 */
 		GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_FP);
 		asm volatile ("fincstp");

 		GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_SSE);
 		asm volatile ("vmovdqu %0, %%xmm0" :: "m" (buffer));

 		if (supported_xcr0 & XFEATURE_MASK_YMM)
 			asm volatile ("vmovdqu %0, %%ymm0" :: "m" (buffer));

 		if (supported_xcr0 & XFEATURE_MASK_AVX512) {
 			asm volatile ("kmovq %0, %%k1" :: "r" (-1ull));
 			asm volatile ("vmovupd %0, %%zmm0" :: "m" (buffer));
 			asm volatile ("vmovupd %0, %%zmm16" :: "m" (buffer));
 		}

 		if (this_cpu_has(X86_FEATURE_MPX)) {
 			uint64_t bounds[2] = { 10, 0xffffffffull };
 			uint64_t output[2] = { };

 			GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_BNDREGS);
 			GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_BNDCSR);

 			/*
 			 * Don't bother trying to get BNDCSR into the INUSE
 			 * state.  MSR_IA32_BNDCFGS doesn't count as it isn't
 			 * managed via XSAVE/XRSTOR, and BNDCFGU can only be
 			 * modified by XRSTOR.  Stuffing XSTATE_BV in the host
 			 * is simpler than doing XRSTOR here in the guest.
 			 *
 			 * However, temporarily enable MPX in BNDCFGS so that
 			 * BNDMOV actually loads BND1.  If MPX isn't *fully*
 			 * enabled, all MPX instructions are treated as NOPs.
 			 *
 			 * Hand encode "bndmov (%rax),%bnd1" as support for MPX
 			 * mnemonics/registers has been removed from gcc and
 			 * clang (and was never fully supported by clang).
 			 */
 			wrmsr(MSR_IA32_BNDCFGS, BIT_ULL(0));
 			asm volatile (".byte 0x66,0x0f,0x1a,0x08" :: "a" (bounds));
 			/*
 			 * Hand encode "bndmov %bnd1, (%rax)" to sanity check
 			 * that BND1 actually got loaded.
 			 */
 			asm volatile (".byte 0x66,0x0f,0x1b,0x08" :: "a" (output));
 			wrmsr(MSR_IA32_BNDCFGS, 0);

 			GUEST_ASSERT_EQ(bounds[0], output[0]);
 			GUEST_ASSERT_EQ(bounds[1], output[1]);
 		}
 		if (this_cpu_has(X86_FEATURE_PKU)) {
 			GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_PKRU);
 			set_cr4(get_cr4() | X86_CR4_PKE);
 			GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSPKE));

 			wrpkru(-1u);
 		}
 	}

 	GUEST_SYNC(2);

 	if (arg) {
 		if (this_cpu_has(X86_FEATURE_SVM))
 			svm_l1_guest_code(arg);
 		else
 			vmx_l1_guest_code(arg);
 	}

 	GUEST_DONE();
 }

 int main(int argc, char *argv[])
 {
 	uint64_t *xstate_bv, saved_xstate_bv;
 	vm_vaddr_t nested_gva = 0;
 	struct kvm_cpuid2 empty_cpuid = {};
 	struct kvm_regs regs1, regs2;
 	struct kvm_vcpu *vcpu, *vcpuN;
 	struct kvm_vm *vm;
 	struct kvm_x86_state *state;
 	struct ucall uc;
 	int stage;

 	/* Create VM */
 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);

 	vcpu_regs_get(vcpu, &regs1);

 	if (kvm_has_cap(KVM_CAP_NESTED_STATE)) {
 		if (kvm_cpu_has(X86_FEATURE_SVM))
 			vcpu_alloc_svm(vm, &nested_gva);
 		else if (kvm_cpu_has(X86_FEATURE_VMX))
 			vcpu_alloc_vmx(vm, &nested_gva);
 	}

 	if (!nested_gva)
 		pr_info("will skip nested state checks\n");

 	vcpu_args_set(vcpu, 1, nested_gva);

 	for (stage = 1;; stage++) {
 		vcpu_run(vcpu);
 		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);

 		switch (get_ucall(vcpu, &uc)) {
 		case UCALL_ABORT:
 			REPORT_GUEST_ASSERT(uc);
 			/* NOT REACHED */
 		case UCALL_SYNC:
 			break;
 		case UCALL_DONE:
 			goto done;
 		default:
 			TEST_FAIL("Unknown ucall %lu", uc.cmd);
 		}

 		/* UCALL_SYNC is handled here.  */
 		TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
 			    uc.args[1] == stage, "Stage %d: Unexpected register values vmexit, got %lx",
 			    stage, (ulong)uc.args[1]);

 		state = vcpu_save_state(vcpu);
 		memset(&regs1, 0, sizeof(regs1));
 		vcpu_regs_get(vcpu, &regs1);

 		kvm_vm_release(vm);

 		/* Restore state in a new VM.  */
 		vcpu = vm_recreate_with_one_vcpu(vm);
 		vcpu_load_state(vcpu, state);

 		/*
 		 * Restore XSAVE state in a dummy vCPU, first without doing
 		 * KVM_SET_CPUID2, and then with an empty guest CPUID.  Except
 		 * for off-by-default xfeatures, e.g. AMX, KVM is supposed to
 		 * allow KVM_SET_XSAVE regardless of guest CPUID.  Manually
 		 * load only XSAVE state, MSRs in particular have a much more
 		 * convoluted ABI.
 		 *
 		 * Load two versions of XSAVE state: one with the actual guest
 		 * XSAVE state, and one with all supported features forced "on"
 		 * in xstate_bv, e.g. to ensure that KVM allows loading all
 		 * supported features, even if something goes awry in saving
 		 * the original snapshot.
 		 */
 		xstate_bv = (void *)&((uint8_t *)state->xsave->region)[512];
 		saved_xstate_bv = *xstate_bv;

 		vcpuN = __vm_vcpu_add(vm, vcpu->id + 1);
 		vcpu_xsave_set(vcpuN, state->xsave);
 		*xstate_bv = kvm_cpu_supported_xcr0();
 		vcpu_xsave_set(vcpuN, state->xsave);

 		vcpu_init_cpuid(vcpuN, &empty_cpuid);
 		vcpu_xsave_set(vcpuN, state->xsave);
 		*xstate_bv = saved_xstate_bv;
 		vcpu_xsave_set(vcpuN, state->xsave);

 		kvm_x86_state_cleanup(state);

 		memset(&regs2, 0, sizeof(regs2));
 		vcpu_regs_get(vcpu, &regs2);
 		TEST_ASSERT(!memcmp(&regs1, &regs2, sizeof(regs2)),
 			    "Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",
 			    (ulong) regs2.rdi, (ulong) regs2.rsi);
 	}

 done:
 	kvm_vm_free(vm);
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* KVM_GET/SET_* tests
	*
	* Copyright (C) 2018, Red Hat, Inc.
	*
	* Tests for vCPU state save/restore, including nested guest state.
	*/
	#include <fcntl.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/ioctl.h>

	#include "test_util.h"

	#include "kvm_util.h"
	#include "processor.h"
	#include "vmx.h"
	#include "svm_util.h"

	#define L2_GUEST_STACK_SIZE 256

	void svm_l2_guest_code(void)
	{
	GUEST_SYNC(4);
	/* Exit to L1 */
	vmcall();
	GUEST_SYNC(6);
	/* Done, exit to L1 and never come back. */
	vmcall();
	}

	static void svm_l1_guest_code(struct svm_test_data *svm)
	{
	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
	struct vmcb *vmcb = svm->vmcb;

	GUEST_ASSERT(svm->vmcb_gpa);
	/* Prepare for L2 execution. */
	generic_svm_setup(svm, svm_l2_guest_code,
	&l2_guest_stack[L2_GUEST_STACK_SIZE]);

	GUEST_SYNC(3);
	run_guest(vmcb, svm->vmcb_gpa);
	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
	GUEST_SYNC(5);
	vmcb->save.rip += 3;
	run_guest(vmcb, svm->vmcb_gpa);
	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
	GUEST_SYNC(7);
	}

	void vmx_l2_guest_code(void)
	{
	GUEST_SYNC(6);

	/* Exit to L1 */
	vmcall();

	/* L1 has now set up a shadow VMCS for us. */
	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
	GUEST_SYNC(10);
	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
	GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0fffee));
	GUEST_SYNC(11);
	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0fffee);
	GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0ffffee));
	GUEST_SYNC(12);

	/* Done, exit to L1 and never come back. */
	vmcall();
	}

	static void vmx_l1_guest_code(struct vmx_pages *vmx_pages)
	{
	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];

	GUEST_ASSERT(vmx_pages->vmcs_gpa);
	GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
	GUEST_SYNC(3);
	GUEST_ASSERT(load_vmcs(vmx_pages));
	GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);

	GUEST_SYNC(4);
	GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);

	prepare_vmcs(vmx_pages, vmx_l2_guest_code,
	&l2_guest_stack[L2_GUEST_STACK_SIZE]);

	GUEST_SYNC(5);
	GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
	GUEST_ASSERT(!vmlaunch());
	GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

	/* Check that the launched state is preserved. */
	GUEST_ASSERT(vmlaunch());

	GUEST_ASSERT(!vmresume());
	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

	GUEST_SYNC(7);
	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

	GUEST_ASSERT(!vmresume());
	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

	vmwrite(GUEST_RIP, vmreadz(GUEST_RIP) + 3);

	vmwrite(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_SHADOW_VMCS);
	vmwrite(VMCS_LINK_POINTER, vmx_pages->shadow_vmcs_gpa);

	GUEST_ASSERT(!vmptrld(vmx_pages->shadow_vmcs_gpa));
	GUEST_ASSERT(vmlaunch());
	GUEST_SYNC(8);
	GUEST_ASSERT(vmlaunch());
	GUEST_ASSERT(vmresume());

	vmwrite(GUEST_RIP, 0xc0ffee);
	GUEST_SYNC(9);
	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);

	GUEST_ASSERT(!vmptrld(vmx_pages->vmcs_gpa));
	GUEST_ASSERT(!vmresume());
	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

	GUEST_ASSERT(!vmptrld(vmx_pages->shadow_vmcs_gpa));
	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffffee);
	GUEST_ASSERT(vmlaunch());
	GUEST_ASSERT(vmresume());
	GUEST_SYNC(13);
	GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffffee);
	GUEST_ASSERT(vmlaunch());
	GUEST_ASSERT(vmresume());
	}

	static void __attribute__((__flatten__)) guest_code(void *arg)
	{
	GUEST_SYNC(1);

	if (this_cpu_has(X86_FEATURE_XSAVE)) {
	uint64_t supported_xcr0 = this_cpu_supported_xcr0();
	uint8_t buffer[4096];

	memset(buffer, 0xcc, sizeof(buffer));

	set_cr4(get_cr4() \| X86_CR4_OSXSAVE);
	GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));

	xsetbv(0, xgetbv(0) \| supported_xcr0);

	/*
	* Modify state for all supported xfeatures to take them out of
	* their "init" state, i.e. to make them show up in XSTATE_BV.
	*
	* Note off-by-default features, e.g. AMX, are out of scope for
	* this particular testcase as they have a different ABI.
	*/
	GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_FP);
	asm volatile ("fincstp");

	GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_SSE);
	asm volatile ("vmovdqu %0, %%xmm0" :: "m" (buffer));

	if (supported_xcr0 & XFEATURE_MASK_YMM)
	asm volatile ("vmovdqu %0, %%ymm0" :: "m" (buffer));

	if (supported_xcr0 & XFEATURE_MASK_AVX512) {
	asm volatile ("kmovq %0, %%k1" :: "r" (-1ull));
	asm volatile ("vmovupd %0, %%zmm0" :: "m" (buffer));
	asm volatile ("vmovupd %0, %%zmm16" :: "m" (buffer));
	}

	if (this_cpu_has(X86_FEATURE_MPX)) {
	uint64_t bounds[2] = { 10, 0xffffffffull };
	uint64_t output[2] = { };

	GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_BNDREGS);
	GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_BNDCSR);

	/*
	* Don't bother trying to get BNDCSR into the INUSE
	* state. MSR_IA32_BNDCFGS doesn't count as it isn't
	* managed via XSAVE/XRSTOR, and BNDCFGU can only be
	* modified by XRSTOR. Stuffing XSTATE_BV in the host
	* is simpler than doing XRSTOR here in the guest.
	*
	* However, temporarily enable MPX in BNDCFGS so that
	* BNDMOV actually loads BND1. If MPX isn't fully
	* enabled, all MPX instructions are treated as NOPs.
	*
	* Hand encode "bndmov (%rax),%bnd1" as support for MPX
	* mnemonics/registers has been removed from gcc and
	* clang (and was never fully supported by clang).
	*/
	wrmsr(MSR_IA32_BNDCFGS, BIT_ULL(0));
	asm volatile (".byte 0x66,0x0f,0x1a,0x08" :: "a" (bounds));
	/*
	* Hand encode "bndmov %bnd1, (%rax)" to sanity check
	* that BND1 actually got loaded.
	*/
	asm volatile (".byte 0x66,0x0f,0x1b,0x08" :: "a" (output));
	wrmsr(MSR_IA32_BNDCFGS, 0);

	GUEST_ASSERT_EQ(bounds[0], output[0]);
	GUEST_ASSERT_EQ(bounds[1], output[1]);
	}
	if (this_cpu_has(X86_FEATURE_PKU)) {
	GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_PKRU);
	set_cr4(get_cr4() \| X86_CR4_PKE);
	GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSPKE));

	wrpkru(-1u);
	}
	}

	GUEST_SYNC(2);

	if (arg) {
	if (this_cpu_has(X86_FEATURE_SVM))
	svm_l1_guest_code(arg);
	else
	vmx_l1_guest_code(arg);
	}

	GUEST_DONE();
	}

	int main(int argc, char *argv[])
	{
	uint64_t *xstate_bv, saved_xstate_bv;
	vm_vaddr_t nested_gva = 0;
	struct kvm_cpuid2 empty_cpuid = {};
	struct kvm_regs regs1, regs2;
	struct kvm_vcpu vcpu, vcpuN;
	struct kvm_vm *vm;
	struct kvm_x86_state *state;
	struct ucall uc;
	int stage;

	/* Create VM */
	vm = vm_create_with_one_vcpu(&vcpu, guest_code);

	vcpu_regs_get(vcpu, &regs1);

	if (kvm_has_cap(KVM_CAP_NESTED_STATE)) {
	if (kvm_cpu_has(X86_FEATURE_SVM))
	vcpu_alloc_svm(vm, &nested_gva);
	else if (kvm_cpu_has(X86_FEATURE_VMX))
	vcpu_alloc_vmx(vm, &nested_gva);
	}

	if (!nested_gva)
	pr_info("will skip nested state checks\n");

	vcpu_args_set(vcpu, 1, nested_gva);

	for (stage = 1;; stage++) {
	vcpu_run(vcpu);
	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);

	switch (get_ucall(vcpu, &uc)) {
	case UCALL_ABORT:
	REPORT_GUEST_ASSERT(uc);
	/* NOT REACHED */
	case UCALL_SYNC:
	break;
	case UCALL_DONE:
	goto done;
	default:
	TEST_FAIL("Unknown ucall %lu", uc.cmd);
	}

	/* UCALL_SYNC is handled here. */
	TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
	uc.args[1] == stage, "Stage %d: Unexpected register values vmexit, got %lx",
	stage, (ulong)uc.args[1]);

	state = vcpu_save_state(vcpu);
	memset(&regs1, 0, sizeof(regs1));
	vcpu_regs_get(vcpu, &regs1);

	kvm_vm_release(vm);

	/* Restore state in a new VM. */
	vcpu = vm_recreate_with_one_vcpu(vm);
	vcpu_load_state(vcpu, state);

	/*
	* Restore XSAVE state in a dummy vCPU, first without doing
	* KVM_SET_CPUID2, and then with an empty guest CPUID. Except
	* for off-by-default xfeatures, e.g. AMX, KVM is supposed to
	* allow KVM_SET_XSAVE regardless of guest CPUID. Manually
	* load only XSAVE state, MSRs in particular have a much more
	* convoluted ABI.
	*
	* Load two versions of XSAVE state: one with the actual guest
	* XSAVE state, and one with all supported features forced "on"
	* in xstate_bv, e.g. to ensure that KVM allows loading all
	* supported features, even if something goes awry in saving
	* the original snapshot.
	*/
	xstate_bv = (void )&((uint8_t )state->xsave->region)[512];
	saved_xstate_bv = *xstate_bv;

	vcpuN = __vm_vcpu_add(vm, vcpu->id + 1);
	vcpu_xsave_set(vcpuN, state->xsave);
	*xstate_bv = kvm_cpu_supported_xcr0();
	vcpu_xsave_set(vcpuN, state->xsave);

	vcpu_init_cpuid(vcpuN, &empty_cpuid);
	vcpu_xsave_set(vcpuN, state->xsave);
	*xstate_bv = saved_xstate_bv;
	vcpu_xsave_set(vcpuN, state->xsave);

	kvm_x86_state_cleanup(state);

	memset(&regs2, 0, sizeof(regs2));
	vcpu_regs_get(vcpu, &regs2);
	TEST_ASSERT(!memcmp(&regs1, &regs2, sizeof(regs2)),
	"Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",
	(ulong) regs2.rdi, (ulong) regs2.rsi);
	}

	done:
	kvm_vm_free(vm);
	}