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

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Test for x86 KVM_CAP_SYNC_REGS
  *
  * Copyright (C) 2018, Google LLC.
  *
  * Verifies expected behavior of x86 KVM_CAP_SYNC_REGS functionality,
  * including requesting an invalid register set, updates to/from values
  * in kvm_run.s.regs when kvm_valid_regs and kvm_dirty_regs are toggled.
  */

 #define _GNU_SOURCE /* for program_invocation_short_name */
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <pthread.h>

 #include "test_util.h"
 #include "kvm_util.h"
 #include "processor.h"

 #define UCALL_PIO_PORT ((uint16_t)0x1000)

 struct ucall uc_none = {
 	.cmd = UCALL_NONE,
 };

 /*
  * ucall is embedded here to protect against compiler reshuffling registers
  * before calling a function. In this test we only need to get KVM_EXIT_IO
  * vmexit and preserve RBX, no additional information is needed.
  */
 void guest_code(void)
 {
 	asm volatile("1: in %[port], %%al\n"
 		     "add $0x1, %%rbx\n"
 		     "jmp 1b"
 		     : : [port] "d" (UCALL_PIO_PORT), "D" (&uc_none)
 		     : "rax", "rbx");
 }

 static void compare_regs(struct kvm_regs *left, struct kvm_regs *right)
 {
 #define REG_COMPARE(reg) \
 	TEST_ASSERT(left->reg == right->reg, \
 		    "Register " #reg \
 		    " values did not match: 0x%llx, 0x%llx", \
 		    left->reg, right->reg)
 	REG_COMPARE(rax);
 	REG_COMPARE(rbx);
 	REG_COMPARE(rcx);
 	REG_COMPARE(rdx);
 	REG_COMPARE(rsi);
 	REG_COMPARE(rdi);
 	REG_COMPARE(rsp);
 	REG_COMPARE(rbp);
 	REG_COMPARE(r8);
 	REG_COMPARE(r9);
 	REG_COMPARE(r10);
 	REG_COMPARE(r11);
 	REG_COMPARE(r12);
 	REG_COMPARE(r13);
 	REG_COMPARE(r14);
 	REG_COMPARE(r15);
 	REG_COMPARE(rip);
 	REG_COMPARE(rflags);
 #undef REG_COMPARE
 }

 static void compare_sregs(struct kvm_sregs *left, struct kvm_sregs *right)
 {
 }

 static void compare_vcpu_events(struct kvm_vcpu_events *left,
 				struct kvm_vcpu_events *right)
 {
 }

 #define TEST_SYNC_FIELDS   (KVM_SYNC_X86_REGS|KVM_SYNC_X86_SREGS|KVM_SYNC_X86_EVENTS)
 #define INVALID_SYNC_FIELD 0x80000000

 /*
  * Set an exception as pending *and* injected while KVM is processing events.
  * KVM is supposed to ignore/drop pending exceptions if userspace is also
  * requesting that an exception be injected.
  */
 static void *race_events_inj_pen(void *arg)
 {
 	struct kvm_run *run = (struct kvm_run *)arg;
 	struct kvm_vcpu_events *events = &run->s.regs.events;

 	WRITE_ONCE(events->exception.nr, UD_VECTOR);

 	for (;;) {
 		WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_EVENTS);
 		WRITE_ONCE(events->flags, 0);
 		WRITE_ONCE(events->exception.injected, 1);
 		WRITE_ONCE(events->exception.pending, 1);

 		pthread_testcancel();
 	}

 	return NULL;
 }

 /*
  * Set an invalid exception vector while KVM is processing events.  KVM is
  * supposed to reject any vector >= 32, as well as NMIs (vector 2).
  */
 static void *race_events_exc(void *arg)
 {
 	struct kvm_run *run = (struct kvm_run *)arg;
 	struct kvm_vcpu_events *events = &run->s.regs.events;

 	for (;;) {
 		WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_EVENTS);
 		WRITE_ONCE(events->flags, 0);
 		WRITE_ONCE(events->exception.nr, UD_VECTOR);
 		WRITE_ONCE(events->exception.pending, 1);
 		WRITE_ONCE(events->exception.nr, 255);

 		pthread_testcancel();
 	}

 	return NULL;
 }

 /*
  * Toggle CR4.PAE while KVM is processing SREGS, EFER.LME=1 with CR4.PAE=0 is
  * illegal, and KVM's MMU heavily relies on vCPU state being valid.
  */
 static noinline void *race_sregs_cr4(void *arg)
 {
 	struct kvm_run *run = (struct kvm_run *)arg;
 	__u64 *cr4 = &run->s.regs.sregs.cr4;
 	__u64 pae_enabled = *cr4;
 	__u64 pae_disabled = *cr4 & ~X86_CR4_PAE;

 	for (;;) {
 		WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_SREGS);
 		WRITE_ONCE(*cr4, pae_enabled);
 		asm volatile(".rept 512\n\t"
 			     "nop\n\t"
 			     ".endr");
 		WRITE_ONCE(*cr4, pae_disabled);

 		pthread_testcancel();
 	}

 	return NULL;
 }

 static void race_sync_regs(void *racer)
 {
 	const time_t TIMEOUT = 2; /* seconds, roughly */
 	struct kvm_x86_state *state;
 	struct kvm_translation tr;
 	struct kvm_vcpu *vcpu;
 	struct kvm_run *run;
 	struct kvm_vm *vm;
 	pthread_t thread;
 	time_t t;

 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
 	run = vcpu->run;

 	run->kvm_valid_regs = KVM_SYNC_X86_SREGS;
 	vcpu_run(vcpu);
 	run->kvm_valid_regs = 0;

 	/* Save state *before* spawning the thread that mucks with vCPU state. */
 	state = vcpu_save_state(vcpu);

 	/*
 	 * Selftests run 64-bit guests by default, both EFER.LME and CR4.PAE
 	 * should already be set in guest state.
 	 */
 	TEST_ASSERT((run->s.regs.sregs.cr4 & X86_CR4_PAE) &&
 		    (run->s.regs.sregs.efer & EFER_LME),
 		    "vCPU should be in long mode, CR4.PAE=%d, EFER.LME=%d",
 		    !!(run->s.regs.sregs.cr4 & X86_CR4_PAE),
 		    !!(run->s.regs.sregs.efer & EFER_LME));

 	TEST_ASSERT_EQ(pthread_create(&thread, NULL, racer, (void *)run), 0);

 	for (t = time(NULL) + TIMEOUT; time(NULL) < t;) {
 		/*
 		 * Reload known good state if the vCPU triple faults, e.g. due
 		 * to the unhandled #GPs being injected.  VMX preserves state
 		 * on shutdown, but SVM synthesizes an INIT as the VMCB state
 		 * is architecturally undefined on triple fault.
 		 */
 		if (!__vcpu_run(vcpu) && run->exit_reason == KVM_EXIT_SHUTDOWN)
 			vcpu_load_state(vcpu, state);

 		if (racer == race_sregs_cr4) {
 			tr = (struct kvm_translation) { .linear_address = 0 };
 			__vcpu_ioctl(vcpu, KVM_TRANSLATE, &tr);
 		}
 	}

 	TEST_ASSERT_EQ(pthread_cancel(thread), 0);
 	TEST_ASSERT_EQ(pthread_join(thread, NULL), 0);

 	kvm_x86_state_cleanup(state);
 	kvm_vm_free(vm);
 }

 int main(int argc, char *argv[])
 {
 	struct kvm_vcpu *vcpu;
 	struct kvm_vm *vm;
 	struct kvm_run *run;
 	struct kvm_regs regs;
 	struct kvm_sregs sregs;
 	struct kvm_vcpu_events events;
 	int rv, cap;

 	cap = kvm_check_cap(KVM_CAP_SYNC_REGS);
 	TEST_REQUIRE((cap & TEST_SYNC_FIELDS) == TEST_SYNC_FIELDS);
 	TEST_REQUIRE(!(cap & INVALID_SYNC_FIELD));

 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);

 	run = vcpu->run;

 	/* Request reading invalid register set from VCPU. */
 	run->kvm_valid_regs = INVALID_SYNC_FIELD;
 	rv = _vcpu_run(vcpu);
 	TEST_ASSERT(rv < 0 && errno == EINVAL,
 		    "Invalid kvm_valid_regs did not cause expected KVM_RUN error: %d",
 		    rv);
 	run->kvm_valid_regs = 0;

 	run->kvm_valid_regs = INVALID_SYNC_FIELD | TEST_SYNC_FIELDS;
 	rv = _vcpu_run(vcpu);
 	TEST_ASSERT(rv < 0 && errno == EINVAL,
 		    "Invalid kvm_valid_regs did not cause expected KVM_RUN error: %d",
 		    rv);
 	run->kvm_valid_regs = 0;

 	/* Request setting invalid register set into VCPU. */
 	run->kvm_dirty_regs = INVALID_SYNC_FIELD;
 	rv = _vcpu_run(vcpu);
 	TEST_ASSERT(rv < 0 && errno == EINVAL,
 		    "Invalid kvm_dirty_regs did not cause expected KVM_RUN error: %d",
 		    rv);
 	run->kvm_dirty_regs = 0;

 	run->kvm_dirty_regs = INVALID_SYNC_FIELD | TEST_SYNC_FIELDS;
 	rv = _vcpu_run(vcpu);
 	TEST_ASSERT(rv < 0 && errno == EINVAL,
 		    "Invalid kvm_dirty_regs did not cause expected KVM_RUN error: %d",
 		    rv);
 	run->kvm_dirty_regs = 0;

 	/* Request and verify all valid register sets. */
 	/* TODO: BUILD TIME CHECK: TEST_ASSERT(KVM_SYNC_X86_NUM_FIELDS != 3); */
 	run->kvm_valid_regs = TEST_SYNC_FIELDS;
 	rv = _vcpu_run(vcpu);
 	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);

 	vcpu_regs_get(vcpu, &regs);
 	compare_regs(&regs, &run->s.regs.regs);

 	vcpu_sregs_get(vcpu, &sregs);
 	compare_sregs(&sregs, &run->s.regs.sregs);

 	vcpu_events_get(vcpu, &events);
 	compare_vcpu_events(&events, &run->s.regs.events);

 	/* Set and verify various register values. */
 	run->s.regs.regs.rbx = 0xBAD1DEA;
 	run->s.regs.sregs.apic_base = 1 << 11;
 	/* TODO run->s.regs.events.XYZ = ABC; */

 	run->kvm_valid_regs = TEST_SYNC_FIELDS;
 	run->kvm_dirty_regs = KVM_SYNC_X86_REGS | KVM_SYNC_X86_SREGS;
 	rv = _vcpu_run(vcpu);
 	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
 	TEST_ASSERT(run->s.regs.regs.rbx == 0xBAD1DEA + 1,
 		    "rbx sync regs value incorrect 0x%llx.",
 		    run->s.regs.regs.rbx);
 	TEST_ASSERT(run->s.regs.sregs.apic_base == 1 << 11,
 		    "apic_base sync regs value incorrect 0x%llx.",
 		    run->s.regs.sregs.apic_base);

 	vcpu_regs_get(vcpu, &regs);
 	compare_regs(&regs, &run->s.regs.regs);

 	vcpu_sregs_get(vcpu, &sregs);
 	compare_sregs(&sregs, &run->s.regs.sregs);

 	vcpu_events_get(vcpu, &events);
 	compare_vcpu_events(&events, &run->s.regs.events);

 	/* Clear kvm_dirty_regs bits, verify new s.regs values are
 	 * overwritten with existing guest values.
 	 */
 	run->kvm_valid_regs = TEST_SYNC_FIELDS;
 	run->kvm_dirty_regs = 0;
 	run->s.regs.regs.rbx = 0xDEADBEEF;
 	rv = _vcpu_run(vcpu);
 	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
 	TEST_ASSERT(run->s.regs.regs.rbx != 0xDEADBEEF,
 		    "rbx sync regs value incorrect 0x%llx.",
 		    run->s.regs.regs.rbx);

 	/* Clear kvm_valid_regs bits and kvm_dirty_bits.
 	 * Verify s.regs values are not overwritten with existing guest values
 	 * and that guest values are not overwritten with kvm_sync_regs values.
 	 */
 	run->kvm_valid_regs = 0;
 	run->kvm_dirty_regs = 0;
 	run->s.regs.regs.rbx = 0xAAAA;
 	regs.rbx = 0xBAC0;
 	vcpu_regs_set(vcpu, &regs);
 	rv = _vcpu_run(vcpu);
 	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
 	TEST_ASSERT(run->s.regs.regs.rbx == 0xAAAA,
 		    "rbx sync regs value incorrect 0x%llx.",
 		    run->s.regs.regs.rbx);
 	vcpu_regs_get(vcpu, &regs);
 	TEST_ASSERT(regs.rbx == 0xBAC0 + 1,
 		    "rbx guest value incorrect 0x%llx.",
 		    regs.rbx);

 	/* Clear kvm_valid_regs bits. Verify s.regs values are not overwritten
 	 * with existing guest values but that guest values are overwritten
 	 * with kvm_sync_regs values.
 	 */
 	run->kvm_valid_regs = 0;
 	run->kvm_dirty_regs = TEST_SYNC_FIELDS;
 	run->s.regs.regs.rbx = 0xBBBB;
 	rv = _vcpu_run(vcpu);
 	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
 	TEST_ASSERT(run->s.regs.regs.rbx == 0xBBBB,
 		    "rbx sync regs value incorrect 0x%llx.",
 		    run->s.regs.regs.rbx);
 	vcpu_regs_get(vcpu, &regs);
 	TEST_ASSERT(regs.rbx == 0xBBBB + 1,
 		    "rbx guest value incorrect 0x%llx.",
 		    regs.rbx);

 	kvm_vm_free(vm);

 	race_sync_regs(race_sregs_cr4);
 	race_sync_regs(race_events_exc);
 	race_sync_regs(race_events_inj_pen);

 	return 0;
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Test for x86 KVM_CAP_SYNC_REGS
	*
	* Copyright (C) 2018, Google LLC.
	*
	* Verifies expected behavior of x86 KVM_CAP_SYNC_REGS functionality,
	* including requesting an invalid register set, updates to/from values
	* in kvm_run.s.regs when kvm_valid_regs and kvm_dirty_regs are toggled.
	*/

	#define _GNU_SOURCE /* for program_invocation_short_name */
	#include <fcntl.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/ioctl.h>
	#include <pthread.h>

	#include "test_util.h"
	#include "kvm_util.h"
	#include "processor.h"

	#define UCALL_PIO_PORT ((uint16_t)0x1000)

	struct ucall uc_none = {
	.cmd = UCALL_NONE,
	};

	/*
	* ucall is embedded here to protect against compiler reshuffling registers
	* before calling a function. In this test we only need to get KVM_EXIT_IO
	* vmexit and preserve RBX, no additional information is needed.
	*/
	void guest_code(void)
	{
	asm volatile("1: in %[port], %%al\n"
	"add $0x1, %%rbx\n"
	"jmp 1b"
	: : [port] "d" (UCALL_PIO_PORT), "D" (&uc_none)
	: "rax", "rbx");
	}

	static void compare_regs(struct kvm_regs left, struct kvm_regs right)
	{
	#define REG_COMPARE(reg) \
	TEST_ASSERT(left->reg == right->reg, \
	"Register " #reg \
	" values did not match: 0x%llx, 0x%llx", \
	left->reg, right->reg)
	REG_COMPARE(rax);
	REG_COMPARE(rbx);
	REG_COMPARE(rcx);
	REG_COMPARE(rdx);
	REG_COMPARE(rsi);
	REG_COMPARE(rdi);
	REG_COMPARE(rsp);
	REG_COMPARE(rbp);
	REG_COMPARE(r8);
	REG_COMPARE(r9);
	REG_COMPARE(r10);
	REG_COMPARE(r11);
	REG_COMPARE(r12);
	REG_COMPARE(r13);
	REG_COMPARE(r14);
	REG_COMPARE(r15);
	REG_COMPARE(rip);
	REG_COMPARE(rflags);
	#undef REG_COMPARE
	}

	static void compare_sregs(struct kvm_sregs left, struct kvm_sregs right)
	{
	}

	static void compare_vcpu_events(struct kvm_vcpu_events *left,
	struct kvm_vcpu_events *right)
	{
	}

	#define TEST_SYNC_FIELDS (KVM_SYNC_X86_REGS\|KVM_SYNC_X86_SREGS\|KVM_SYNC_X86_EVENTS)
	#define INVALID_SYNC_FIELD 0x80000000

	/*
	* Set an exception as pending and injected while KVM is processing events.
	* KVM is supposed to ignore/drop pending exceptions if userspace is also
	* requesting that an exception be injected.
	*/
	static void race_events_inj_pen(void arg)
	{
	struct kvm_run run = (struct kvm_run )arg;
	struct kvm_vcpu_events *events = &run->s.regs.events;

	WRITE_ONCE(events->exception.nr, UD_VECTOR);

	for (;;) {
	WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_EVENTS);
	WRITE_ONCE(events->flags, 0);
	WRITE_ONCE(events->exception.injected, 1);
	WRITE_ONCE(events->exception.pending, 1);

	pthread_testcancel();
	}

	return NULL;
	}

	/*
	* Set an invalid exception vector while KVM is processing events. KVM is
	* supposed to reject any vector >= 32, as well as NMIs (vector 2).
	*/
	static void race_events_exc(void arg)
	{
	struct kvm_run run = (struct kvm_run )arg;
	struct kvm_vcpu_events *events = &run->s.regs.events;

	for (;;) {
	WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_EVENTS);
	WRITE_ONCE(events->flags, 0);
	WRITE_ONCE(events->exception.nr, UD_VECTOR);
	WRITE_ONCE(events->exception.pending, 1);
	WRITE_ONCE(events->exception.nr, 255);

	pthread_testcancel();
	}

	return NULL;
	}

	/*
	* Toggle CR4.PAE while KVM is processing SREGS, EFER.LME=1 with CR4.PAE=0 is
	* illegal, and KVM's MMU heavily relies on vCPU state being valid.
	*/
	static noinline void race_sregs_cr4(void arg)
	{
	struct kvm_run run = (struct kvm_run )arg;
	__u64 *cr4 = &run->s.regs.sregs.cr4;
	__u64 pae_enabled = *cr4;
	__u64 pae_disabled = *cr4 & ~X86_CR4_PAE;

	for (;;) {
	WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_SREGS);
	WRITE_ONCE(*cr4, pae_enabled);
	asm volatile(".rept 512\n\t"
	"nop\n\t"
	".endr");
	WRITE_ONCE(*cr4, pae_disabled);

	pthread_testcancel();
	}

	return NULL;
	}

	static void race_sync_regs(void *racer)
	{
	const time_t TIMEOUT = 2; /* seconds, roughly */
	struct kvm_x86_state *state;
	struct kvm_translation tr;
	struct kvm_vcpu *vcpu;
	struct kvm_run *run;
	struct kvm_vm *vm;
	pthread_t thread;
	time_t t;

	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
	run = vcpu->run;

	run->kvm_valid_regs = KVM_SYNC_X86_SREGS;
	vcpu_run(vcpu);
	run->kvm_valid_regs = 0;

	/* Save state before spawning the thread that mucks with vCPU state. */
	state = vcpu_save_state(vcpu);

	/*
	* Selftests run 64-bit guests by default, both EFER.LME and CR4.PAE
	* should already be set in guest state.
	*/
	TEST_ASSERT((run->s.regs.sregs.cr4 & X86_CR4_PAE) &&
	(run->s.regs.sregs.efer & EFER_LME),
	"vCPU should be in long mode, CR4.PAE=%d, EFER.LME=%d",
	!!(run->s.regs.sregs.cr4 & X86_CR4_PAE),
	!!(run->s.regs.sregs.efer & EFER_LME));

	TEST_ASSERT_EQ(pthread_create(&thread, NULL, racer, (void *)run), 0);

	for (t = time(NULL) + TIMEOUT; time(NULL) < t;) {
	/*
	* Reload known good state if the vCPU triple faults, e.g. due
	* to the unhandled #GPs being injected. VMX preserves state
	* on shutdown, but SVM synthesizes an INIT as the VMCB state
	* is architecturally undefined on triple fault.
	*/
	if (!__vcpu_run(vcpu) && run->exit_reason == KVM_EXIT_SHUTDOWN)
	vcpu_load_state(vcpu, state);

	if (racer == race_sregs_cr4) {
	tr = (struct kvm_translation) { .linear_address = 0 };
	__vcpu_ioctl(vcpu, KVM_TRANSLATE, &tr);
	}
	}

	TEST_ASSERT_EQ(pthread_cancel(thread), 0);
	TEST_ASSERT_EQ(pthread_join(thread, NULL), 0);

	kvm_x86_state_cleanup(state);
	kvm_vm_free(vm);
	}

	int main(int argc, char *argv[])
	{
	struct kvm_vcpu *vcpu;
	struct kvm_vm *vm;
	struct kvm_run *run;
	struct kvm_regs regs;
	struct kvm_sregs sregs;
	struct kvm_vcpu_events events;
	int rv, cap;

	cap = kvm_check_cap(KVM_CAP_SYNC_REGS);
	TEST_REQUIRE((cap & TEST_SYNC_FIELDS) == TEST_SYNC_FIELDS);
	TEST_REQUIRE(!(cap & INVALID_SYNC_FIELD));

	vm = vm_create_with_one_vcpu(&vcpu, guest_code);

	run = vcpu->run;

	/* Request reading invalid register set from VCPU. */
	run->kvm_valid_regs = INVALID_SYNC_FIELD;
	rv = _vcpu_run(vcpu);
	TEST_ASSERT(rv < 0 && errno == EINVAL,
	"Invalid kvm_valid_regs did not cause expected KVM_RUN error: %d",
	rv);
	run->kvm_valid_regs = 0;

	run->kvm_valid_regs = INVALID_SYNC_FIELD \| TEST_SYNC_FIELDS;
	rv = _vcpu_run(vcpu);
	TEST_ASSERT(rv < 0 && errno == EINVAL,
	"Invalid kvm_valid_regs did not cause expected KVM_RUN error: %d",
	rv);
	run->kvm_valid_regs = 0;

	/* Request setting invalid register set into VCPU. */
	run->kvm_dirty_regs = INVALID_SYNC_FIELD;
	rv = _vcpu_run(vcpu);
	TEST_ASSERT(rv < 0 && errno == EINVAL,
	"Invalid kvm_dirty_regs did not cause expected KVM_RUN error: %d",
	rv);
	run->kvm_dirty_regs = 0;

	run->kvm_dirty_regs = INVALID_SYNC_FIELD \| TEST_SYNC_FIELDS;
	rv = _vcpu_run(vcpu);
	TEST_ASSERT(rv < 0 && errno == EINVAL,
	"Invalid kvm_dirty_regs did not cause expected KVM_RUN error: %d",
	rv);
	run->kvm_dirty_regs = 0;

	/* Request and verify all valid register sets. */
	/* TODO: BUILD TIME CHECK: TEST_ASSERT(KVM_SYNC_X86_NUM_FIELDS != 3); */
	run->kvm_valid_regs = TEST_SYNC_FIELDS;
	rv = _vcpu_run(vcpu);
	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);

	vcpu_regs_get(vcpu, &regs);
	compare_regs(&regs, &run->s.regs.regs);

	vcpu_sregs_get(vcpu, &sregs);
	compare_sregs(&sregs, &run->s.regs.sregs);

	vcpu_events_get(vcpu, &events);
	compare_vcpu_events(&events, &run->s.regs.events);

	/* Set and verify various register values. */
	run->s.regs.regs.rbx = 0xBAD1DEA;
	run->s.regs.sregs.apic_base = 1 << 11;
	/* TODO run->s.regs.events.XYZ = ABC; */

	run->kvm_valid_regs = TEST_SYNC_FIELDS;
	run->kvm_dirty_regs = KVM_SYNC_X86_REGS \| KVM_SYNC_X86_SREGS;
	rv = _vcpu_run(vcpu);
	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
	TEST_ASSERT(run->s.regs.regs.rbx == 0xBAD1DEA + 1,
	"rbx sync regs value incorrect 0x%llx.",
	run->s.regs.regs.rbx);
	TEST_ASSERT(run->s.regs.sregs.apic_base == 1 << 11,
	"apic_base sync regs value incorrect 0x%llx.",
	run->s.regs.sregs.apic_base);

	vcpu_regs_get(vcpu, &regs);
	compare_regs(&regs, &run->s.regs.regs);

	vcpu_sregs_get(vcpu, &sregs);
	compare_sregs(&sregs, &run->s.regs.sregs);

	vcpu_events_get(vcpu, &events);
	compare_vcpu_events(&events, &run->s.regs.events);

	/* Clear kvm_dirty_regs bits, verify new s.regs values are
	* overwritten with existing guest values.
	*/
	run->kvm_valid_regs = TEST_SYNC_FIELDS;
	run->kvm_dirty_regs = 0;
	run->s.regs.regs.rbx = 0xDEADBEEF;
	rv = _vcpu_run(vcpu);
	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
	TEST_ASSERT(run->s.regs.regs.rbx != 0xDEADBEEF,
	"rbx sync regs value incorrect 0x%llx.",
	run->s.regs.regs.rbx);

	/* Clear kvm_valid_regs bits and kvm_dirty_bits.
	* Verify s.regs values are not overwritten with existing guest values
	* and that guest values are not overwritten with kvm_sync_regs values.
	*/
	run->kvm_valid_regs = 0;
	run->kvm_dirty_regs = 0;
	run->s.regs.regs.rbx = 0xAAAA;
	regs.rbx = 0xBAC0;
	vcpu_regs_set(vcpu, &regs);
	rv = _vcpu_run(vcpu);
	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
	TEST_ASSERT(run->s.regs.regs.rbx == 0xAAAA,
	"rbx sync regs value incorrect 0x%llx.",
	run->s.regs.regs.rbx);
	vcpu_regs_get(vcpu, &regs);
	TEST_ASSERT(regs.rbx == 0xBAC0 + 1,
	"rbx guest value incorrect 0x%llx.",
	regs.rbx);

	/* Clear kvm_valid_regs bits. Verify s.regs values are not overwritten
	* with existing guest values but that guest values are overwritten
	* with kvm_sync_regs values.
	*/
	run->kvm_valid_regs = 0;
	run->kvm_dirty_regs = TEST_SYNC_FIELDS;
	run->s.regs.regs.rbx = 0xBBBB;
	rv = _vcpu_run(vcpu);
	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
	TEST_ASSERT(run->s.regs.regs.rbx == 0xBBBB,
	"rbx sync regs value incorrect 0x%llx.",
	run->s.regs.regs.rbx);
	vcpu_regs_get(vcpu, &regs);
	TEST_ASSERT(regs.rbx == 0xBBBB + 1,
	"rbx guest value incorrect 0x%llx.",
	regs.rbx);

	kvm_vm_free(vm);

	race_sync_regs(race_sregs_cr4);
	race_sync_regs(race_events_exc);
	race_sync_regs(race_events_inj_pen);

	return 0;
	}