Merge tag 'kvm-x86-selftests-6.15' of https://github.com/kvm-x86/linux into HEAD (783e9cd0) · Commits · git / linux-nf

tools/testing/selftests/kvm/dirty_log_test.c

+247 −276

Original line number	Diff line number	Diff line
		@@ -31,15 +31,18 @@
		/* Default guest test virtual memory offset */
		#define DEFAULT_GUEST_TEST_MEM 0xc0000000

		/* How many pages to dirty for each guest loop */
		#define TEST_PAGES_PER_LOOP 1024

		/* How many host loops to run (one KVM_GET_DIRTY_LOG for each loop) */
		#define TEST_HOST_LOOP_N 32UL

		/* Interval for each host loop (ms) */
		#define TEST_HOST_LOOP_INTERVAL 10UL

		/*
		* Ensure the vCPU is able to perform a reasonable number of writes in each
		* iteration to provide a lower bound on coverage.
		*/
		#define TEST_MIN_WRITES_PER_ITERATION 0x100

		/* Dirty bitmaps are always little endian, so we need to swap on big endian */
		#if defined(__s390x__)
		# define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7)
		@@ -75,6 +78,8 @@ static uint64_t host_page_size;
		static uint64_t guest_page_size;
		static uint64_t guest_num_pages;
		static uint64_t iteration;
		static uint64_t nr_writes;
		static bool vcpu_stop;

		/*
		* Guest physical memory offset of the testing memory slot.
		@@ -96,7 +101,9 @@ static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
		static void guest_code(void)
		{
		uint64_t addr;
		int i;

		#ifdef __s390x__
		uint64_t i;

		/*
		* On s390x, all pages of a 1M segment are initially marked as dirty
		@@ -107,16 +114,19 @@ static void guest_code(void)
		for (i = 0; i < guest_num_pages; i++) {
		addr = guest_test_virt_mem + i * guest_page_size;
		vcpu_arch_put_guest((uint64_t )addr, READ_ONCE(iteration));
		nr_writes++;
		}
		#endif

		while (true) {
		for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
		while (!READ_ONCE(vcpu_stop)) {
		addr = guest_test_virt_mem;
		addr += (guest_random_u64(&guest_rng) % guest_num_pages)
		* guest_page_size;
		addr = align_down(addr, host_page_size);

		vcpu_arch_put_guest((uint64_t )addr, READ_ONCE(iteration));
		nr_writes++;
		}

		GUEST_SYNC(1);
		@@ -133,25 +143,18 @@ static uint64_t host_num_pages;
		/* For statistics only */
		static uint64_t host_dirty_count;
		static uint64_t host_clear_count;
		static uint64_t host_track_next_count;

		/* Whether dirty ring reset is requested, or finished */
		static sem_t sem_vcpu_stop;
		static sem_t sem_vcpu_cont;
		/*
		* This is only set by main thread, and only cleared by vcpu thread. It is
		* used to request vcpu thread to stop at the next GUEST_SYNC, since GUEST_SYNC
		* is the only place that we'll guarantee both "dirty bit" and "dirty data"
		* will match. E.g., SIG_IPI won't guarantee that if the vcpu is interrupted
		* after setting dirty bit but before the data is written.
		*/
		static atomic_t vcpu_sync_stop_requested;

		/*
		* This is updated by the vcpu thread to tell the host whether it's a
		* ring-full event. It should only be read until a sem_wait() of
		* sem_vcpu_stop and before vcpu continues to run.
		*/
		static bool dirty_ring_vcpu_ring_full;

		/*
		* This is only used for verifying the dirty pages. Dirty ring has a very
		* tricky case when the ring just got full, kvm will do userspace exit due to
		@@ -166,7 +169,51 @@ static bool dirty_ring_vcpu_ring_full;
		* dirty gfn we've collected, so that if a mismatch of data found later in the
		* verifying process, we let it pass.
		*/
		static uint64_t dirty_ring_last_page;
		static uint64_t dirty_ring_last_page = -1ULL;

		/*
		* In addition to the above, it is possible (especially if this
		* test is run nested) for the above scenario to repeat multiple times:
		*
		* The following can happen:
		*
		* - L1 vCPU: Memory write is logged to PML but not committed.
		*
		* - L1 test thread: Ignores the write because its last dirty ring entry
		* Resets the dirty ring which:
		* - Resets the A/D bits in EPT
		* - Issues tlb flush (invept), which is intercepted by L0
		*
		* - L0: frees the whole nested ept mmu root as the response to invept,
		* and thus ensures that when memory write is retried, it will fault again
		*
		* - L1 vCPU: Same memory write is logged to the PML but not committed again.
		*
		* - L1 test thread: Ignores the write because its last dirty ring entry (again)
		* Resets the dirty ring which:
		* - Resets the A/D bits in EPT (again)
		* - Issues tlb flush (again) which is intercepted by L0
		*
		* ...
		*
		* N times
		*
		* - L1 vCPU: Memory write is logged in the PML and then committed.
		* Lots of other memory writes are logged and committed.
		* ...
		*
		* - L1 test thread: Sees the memory write along with other memory writes
		* in the dirty ring, and since the write is usually not
		* the last entry in the dirty-ring and has a very outdated
		* iteration, the test fails.
		*
		*
		* Note that this is only possible when the write was the last log entry
		* write during iteration N-1, thus remember last iteration last log entry
		* and also don't fail when it is reported in the next iteration, together with
		* an outdated iteration count.
		*/
		static uint64_t dirty_ring_prev_iteration_last_page;

		enum log_mode_t {
		/* Only use KVM_GET_DIRTY_LOG for logging */
		@@ -191,24 +238,6 @@ static enum log_mode_t host_log_mode;
		static pthread_t vcpu_thread;
		static uint32_t test_dirty_ring_count = TEST_DIRTY_RING_COUNT;

		static void vcpu_kick(void)
		{
		pthread_kill(vcpu_thread, SIG_IPI);
		}

		/*
		* In our test we do signal tricks, let's use a better version of
		* sem_wait to avoid signal interrupts
		*/
		static void sem_wait_until(sem_t *sem)
		{
		int ret;

		do
		ret = sem_wait(sem);
		while (ret == -1 && errno == EINTR);
		}

		static bool clear_log_supported(void)
		{
		return kvm_has_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
		@@ -243,21 +272,16 @@ static void clear_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
		/* Should only be called after a GUEST_SYNC */
		static void vcpu_handle_sync_stop(void)
		{
		if (atomic_read(&vcpu_sync_stop_requested)) {
		/* It means main thread is sleeping waiting */
		atomic_set(&vcpu_sync_stop_requested, false);
		if (READ_ONCE(vcpu_stop)) {
		sem_post(&sem_vcpu_stop);
		sem_wait_until(&sem_vcpu_cont);
		sem_wait(&sem_vcpu_cont);
		}
		}

		static void default_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
		static void default_after_vcpu_run(struct kvm_vcpu *vcpu)
		{
		struct kvm_run *run = vcpu->run;

		TEST_ASSERT(ret == 0 \|\| (ret == -1 && err == EINTR),
		"vcpu run failed: errno=%d", err);

		TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC,
		"Invalid guest sync status: exit_reason=%s",
		exit_reason_str(run->exit_reason));
		@@ -324,7 +348,6 @@ static uint32_t dirty_ring_collect_one(struct kvm_dirty_gfn *dirty_gfns,
		"%u != %u", cur->slot, slot);
		TEST_ASSERT(cur->offset < num_pages, "Offset overflow: "
		"0x%llx >= 0x%x", cur->offset, num_pages);
		//pr_info("fetch 0x%x page %llu\n", *fetch_index, cur->offset);
		__set_bit_le(cur->offset, bitmap);
		dirty_ring_last_page = cur->offset;
		dirty_gfn_set_collected(cur);
		@@ -335,36 +358,11 @@ static uint32_t dirty_ring_collect_one(struct kvm_dirty_gfn *dirty_gfns,
		return count;
		}

		static void dirty_ring_wait_vcpu(void)
		{
		/* This makes sure that hardware PML cache flushed */
		vcpu_kick();
		sem_wait_until(&sem_vcpu_stop);
		}

		static void dirty_ring_continue_vcpu(void)
		{
		pr_info("Notifying vcpu to continue\n");
		sem_post(&sem_vcpu_cont);
		}

		static void dirty_ring_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
		void *bitmap, uint32_t num_pages,
		uint32_t *ring_buf_idx)
		{
		uint32_t count = 0, cleared;
		bool continued_vcpu = false;

		dirty_ring_wait_vcpu();

		if (!dirty_ring_vcpu_ring_full) {
		/*
		* This is not a ring-full event, it's safe to allow
		* vcpu to continue
		*/
		dirty_ring_continue_vcpu();
		continued_vcpu = true;
		}
		uint32_t count, cleared;

		/* Only have one vcpu */
		count = dirty_ring_collect_one(vcpu_map_dirty_ring(vcpu),
		@@ -379,35 +377,18 @@ static void dirty_ring_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
		*/
		TEST_ASSERT(cleared == count, "Reset dirty pages (%u) mismatch "
		"with collected (%u)", cleared, count);

		if (!continued_vcpu) {
		TEST_ASSERT(dirty_ring_vcpu_ring_full,
		"Didn't continue vcpu even without ring full");
		dirty_ring_continue_vcpu();
		}

		pr_info("Iteration %ld collected %u pages\n", iteration, count);
		}

		static void dirty_ring_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
		static void dirty_ring_after_vcpu_run(struct kvm_vcpu *vcpu)
		{
		struct kvm_run *run = vcpu->run;

		/* A ucall-sync or ring-full event is allowed */
		if (get_ucall(vcpu, NULL) == UCALL_SYNC) {
		/* We should allow this to continue */
		;
		} else if (run->exit_reason == KVM_EXIT_DIRTY_RING_FULL \|\|
		(ret == -1 && err == EINTR)) {
		/* Update the flag first before pause */
		WRITE_ONCE(dirty_ring_vcpu_ring_full,
		run->exit_reason == KVM_EXIT_DIRTY_RING_FULL);
		sem_post(&sem_vcpu_stop);
		pr_info("vcpu stops because %s...\n",
		dirty_ring_vcpu_ring_full ?
		"dirty ring is full" : "vcpu is kicked out");
		sem_wait_until(&sem_vcpu_cont);
		pr_info("vcpu continues now.\n");
		vcpu_handle_sync_stop();
		} else if (run->exit_reason == KVM_EXIT_DIRTY_RING_FULL) {
		WRITE_ONCE(dirty_ring_vcpu_ring_full, true);
		vcpu_handle_sync_stop();
		} else {
		TEST_ASSERT(false, "Invalid guest sync status: "
		"exit_reason=%s",
		@@ -426,7 +407,7 @@ struct log_mode {
		void *bitmap, uint32_t num_pages,
		uint32_t *ring_buf_idx);
		/* Hook to call when after each vcpu run */
		void (after_vcpu_run)(struct kvm_vcpu vcpu, int ret, int err);
		void (after_vcpu_run)(struct kvm_vcpu vcpu);
		} log_modes[LOG_MODE_NUM] = {
		{
		.name = "dirty-log",
		@@ -449,15 +430,6 @@ struct log_mode {
		},
		};

		/*
		* We use this bitmap to track some pages that should have its dirty
		* bit set in the _next_ iteration. For example, if we detected the
		* page value changed to current iteration but at the same time the
		* page bit is cleared in the latest bitmap, then the system must
		* report that write in the next get dirty log call.
		*/
		static unsigned long *host_bmap_track;

		static void log_modes_dump(void)
		{
		int i;
		@@ -497,170 +469,109 @@ static void log_mode_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
		mode->collect_dirty_pages(vcpu, slot, bitmap, num_pages, ring_buf_idx);
		}

		static void log_mode_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
		static void log_mode_after_vcpu_run(struct kvm_vcpu *vcpu)
		{
		struct log_mode *mode = &log_modes[host_log_mode];

		if (mode->after_vcpu_run)
		mode->after_vcpu_run(vcpu, ret, err);
		mode->after_vcpu_run(vcpu);
		}

		static void vcpu_worker(void data)
		{
		int ret;
		struct kvm_vcpu *vcpu = data;
		uint64_t pages_count = 0;
		struct kvm_signal_mask *sigmask = alloca(offsetof(struct kvm_signal_mask, sigset)
		+ sizeof(sigset_t));
		sigset_t sigset = (sigset_t ) &sigmask->sigset;

		/*
		* SIG_IPI is unblocked atomically while in KVM_RUN. It causes the
		* ioctl to return with -EINTR, but it is still pending and we need
		* to accept it with the sigwait.
		*/
		sigmask->len = 8;
		pthread_sigmask(0, NULL, sigset);
		sigdelset(sigset, SIG_IPI);
		vcpu_ioctl(vcpu, KVM_SET_SIGNAL_MASK, sigmask);

		sigemptyset(sigset);
		sigaddset(sigset, SIG_IPI);
		sem_wait(&sem_vcpu_cont);

		while (!READ_ONCE(host_quit)) {
		/* Clear any existing kick signals */
		pages_count += TEST_PAGES_PER_LOOP;
		/* Let the guest dirty the random pages */
		ret = __vcpu_run(vcpu);
		if (ret == -1 && errno == EINTR) {
		int sig = -1;
		sigwait(sigset, &sig);
		assert(sig == SIG_IPI);
		vcpu_run(vcpu);
		log_mode_after_vcpu_run(vcpu);
		}
		log_mode_after_vcpu_run(vcpu, ret, errno);
		}

		pr_info("Dirtied %"PRIu64" pages\n", pages_count);

		return NULL;
		}

		static void vm_dirty_log_verify(enum vm_guest_mode mode, unsigned long *bmap)
		static void vm_dirty_log_verify(enum vm_guest_mode mode, unsigned long **bmap)
		{
		uint64_t page, nr_dirty_pages = 0, nr_clean_pages = 0;
		uint64_t step = vm_num_host_pages(mode, 1);
		uint64_t page;
		uint64_t *value_ptr;
		uint64_t min_iter = 0;

		for (page = 0; page < host_num_pages; page += step) {
		value_ptr = host_test_mem + page * host_page_size;

		/* If this is a special page that we were tracking... */
		if (__test_and_clear_bit_le(page, host_bmap_track)) {
		host_track_next_count++;
		TEST_ASSERT(test_bit_le(page, bmap),
		"Page %"PRIu64" should have its dirty bit "
		"set in this iteration but it is missing",
		page);
		}
		uint64_t val = (uint64_t )(host_test_mem + page * host_page_size);
		bool bmap0_dirty = __test_and_clear_bit_le(page, bmap[0]);

		if (__test_and_clear_bit_le(page, bmap)) {
		bool matched;
		/*
		* Ensure both bitmaps are cleared, as a page can be written
		* multiple times per iteration, i.e. can show up in both
		* bitmaps, and the dirty ring is additive, i.e. doesn't purge
		* bitmap entries from previous collections.
		*/
		if (__test_and_clear_bit_le(page, bmap[1]) \|\| bmap0_dirty) {
		nr_dirty_pages++;

		host_dirty_count++;
		/*
		* If the page is dirty, the value written to memory
		* should be the current iteration number.
		*/
		if (val == iteration)
		continue;

		if (host_log_mode == LOG_MODE_DIRTY_RING) {
		/*
		* If the bit is set, the value written onto
		* the corresponding page should be either the
		* previous iteration number or the current one.
		* The last page in the ring from previous
		* iteration can be written with the value
		* from the previous iteration, as the value to
		* be written may be cached in a CPU register.
		*/
		matched = (*value_ptr == iteration \|\|
		*value_ptr == iteration - 1);
		if (page == dirty_ring_prev_iteration_last_page &&
		val == iteration - 1)
		continue;

		if (host_log_mode == LOG_MODE_DIRTY_RING && !matched) {
		if (*value_ptr == iteration - 2 && min_iter <= iteration - 2) {
		/*
		* Short answer: this case is special
		* only for dirty ring test where the
		* page is the last page before a kvm
		* dirty ring full in iteration N-2.
		*
		* Long answer: Assuming ring size R,
		* one possible condition is:
		*
		* main thr vcpu thr
		* -------- --------
		* iter=1
		* write 1 to page 0~(R-1)
		* full, vmexit
		* collect 0~(R-1)
		* kick vcpu
		* write 1 to (R-1)~(2R-2)
		* full, vmexit
		* iter=2
		* collect (R-1)~(2R-2)
		* kick vcpu
		* write 1 to (2R-2)
		* (NOTE!!! "1" cached in cpu reg)
		* write 2 to (2R-1)~(3R-3)
		* full, vmexit
		* iter=3
		* collect (2R-2)~(3R-3)
		* (here if we read value on page
		* "2R-2" is 1, while iter=3!!!)
		*
		* This however can only happen once per iteration.
		* Any value from a previous iteration is legal
		* for the last entry, as the write may not yet
		* have retired, i.e. the page may hold whatever
		* it had before this iteration started.
		*/
		min_iter = iteration - 1;
		if (page == dirty_ring_last_page &&
		val < iteration)
		continue;
		} else if (page == dirty_ring_last_page) {
		} else if (!val && iteration == 1 && bmap0_dirty) {
		/*
		* Please refer to comments in
		* dirty_ring_last_page.
		* When testing get+clear, the dirty bitmap
		* starts with all bits set, and so the first
		* iteration can observe a "dirty" page that
		* was never written, but only in the first
		* bitmap (collecting the bitmap also clears
		* all dirty pages).
		*/
		continue;
		}
		}

		TEST_ASSERT(matched,
		"Set page %"PRIu64" value %"PRIu64
		" incorrect (iteration=%"PRIu64")",
		page, *value_ptr, iteration);
		TEST_FAIL("Dirty page %lu value (%lu) != iteration (%lu) "
		"(last = %lu, prev_last = %lu)",
		page, val, iteration, dirty_ring_last_page,
		dirty_ring_prev_iteration_last_page);
		} else {
		host_clear_count++;
		nr_clean_pages++;
		/*
		* If cleared, the value written can be any
		* value smaller or equals to the iteration
		* number. Note that the value can be exactly
		* (iteration-1) if that write can happen
		* like this:
		*
		* (1) increase loop count to "iteration-1"
		* (2) write to page P happens (with value
		* "iteration-1")
		* (3) get dirty log for "iteration-1"; we'll
		* see that page P bit is set (dirtied),
		* and not set the bit in host_bmap_track
		* (4) increase loop count to "iteration"
		* (which is current iteration)
		* (5) get dirty log for current iteration,
		* we'll see that page P is cleared, with
		* value "iteration-1".
		*/
		TEST_ASSERT(*value_ptr <= iteration,
		"Clear page %"PRIu64" value %"PRIu64
		" incorrect (iteration=%"PRIu64")",
		page, *value_ptr, iteration);
		if (*value_ptr == iteration) {
		/*
		* This page is _just_ modified; it
		* should report its dirtyness in the
		* next run
		* value smaller than the iteration number.
		*/
		__set_bit_le(page, host_bmap_track);
		}
		TEST_ASSERT(val < iteration,
		"Clear page %lu value (%lu) >= iteration (%lu) "
		"(last = %lu, prev_last = %lu)",
		page, val, iteration, dirty_ring_last_page,
		dirty_ring_prev_iteration_last_page);
		}
		}

		pr_info("Iteration %2ld: dirty: %-6lu clean: %-6lu writes: %-6lu\n",
		iteration, nr_dirty_pages, nr_clean_pages, nr_writes);

		host_dirty_count += nr_dirty_pages;
		host_clear_count += nr_clean_pages;
		}

		static struct kvm_vm create_vm(enum vm_guest_mode mode, struct kvm_vcpu *vcpu,
		@@ -688,7 +599,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
		struct test_params *p = arg;
		struct kvm_vcpu *vcpu;
		struct kvm_vm *vm;
		unsigned long *bmap;
		unsigned long *bmap[2];
		uint32_t ring_buf_idx = 0;
		int sem_val;

		@@ -731,12 +642,21 @@ static void run_test(enum vm_guest_mode mode, void *arg)
		#ifdef __s390x__
		/* Align to 1M (segment size) */
		guest_test_phys_mem = align_down(guest_test_phys_mem, 1 << 20);

		/*
		* The workaround in guest_code() to write all pages prior to the first
		* iteration isn't compatible with the dirty ring, as the dirty ring
		* support relies on the vCPU to actually stop when vcpu_stop is set so
		* that the vCPU doesn't hang waiting for the dirty ring to be emptied.
		*/
		TEST_ASSERT(host_log_mode != LOG_MODE_DIRTY_RING,
		"Test needs to be updated to support s390 dirty ring");
		#endif

		pr_info("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);

		bmap = bitmap_zalloc(host_num_pages);
		host_bmap_track = bitmap_zalloc(host_num_pages);
		bmap[0] = bitmap_zalloc(host_num_pages);
		bmap[1] = bitmap_zalloc(host_num_pages);

		/* Add an extra memory slot for testing dirty logging */
		vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
		@@ -757,14 +677,9 @@ static void run_test(enum vm_guest_mode mode, void *arg)
		sync_global_to_guest(vm, guest_test_virt_mem);
		sync_global_to_guest(vm, guest_num_pages);

		/* Start the iterations */
		iteration = 1;
		sync_global_to_guest(vm, iteration);
		WRITE_ONCE(host_quit, false);
		host_dirty_count = 0;
		host_clear_count = 0;
		host_track_next_count = 0;
		WRITE_ONCE(dirty_ring_vcpu_ring_full, false);
		WRITE_ONCE(host_quit, false);

		/*
		* Ensure the previous iteration didn't leave a dangling semaphore, i.e.
		@@ -776,21 +691,95 @@ static void run_test(enum vm_guest_mode mode, void *arg)
		sem_getvalue(&sem_vcpu_cont, &sem_val);
		TEST_ASSERT_EQ(sem_val, 0);

		TEST_ASSERT_EQ(vcpu_stop, false);

		pthread_create(&vcpu_thread, NULL, vcpu_worker, vcpu);

		while (iteration < p->iterations) {
		/* Give the vcpu thread some time to dirty some pages */
		usleep(p->interval * 1000);
		for (iteration = 1; iteration <= p->iterations; iteration++) {
		unsigned long i;

		sync_global_to_guest(vm, iteration);

		WRITE_ONCE(nr_writes, 0);
		sync_global_to_guest(vm, nr_writes);

		dirty_ring_prev_iteration_last_page = dirty_ring_last_page;
		WRITE_ONCE(dirty_ring_vcpu_ring_full, false);

		sem_post(&sem_vcpu_cont);

		/*
		* Let the vCPU run beyond the configured interval until it has
		* performed the minimum number of writes. This verifies the
		* guest is making forward progress, e.g. isn't stuck because
		* of a KVM bug, and puts a firm floor on test coverage.
		*/
		for (i = 0; i < p->interval \|\| nr_writes < TEST_MIN_WRITES_PER_ITERATION; i++) {
		/*
		* Sleep in 1ms chunks to keep the interval math simple
		* and so that the test doesn't run too far beyond the
		* specified interval.
		*/
		usleep(1000);

		sync_global_from_guest(vm, nr_writes);

		/*
		* Reap dirty pages while the guest is running so that
		* dirty ring full events are resolved, i.e. so that a
		* larger interval doesn't always end up with a vCPU
		* that's effectively blocked. Collecting while the
		* guest is running also verifies KVM doesn't lose any
		* state.
		*
		* For bitmap modes, KVM overwrites the entire bitmap,
		* i.e. collecting the bitmaps is destructive. Collect
		* the bitmap only on the first pass, otherwise this
		* test would lose track of dirty pages.
		*/
		if (i && host_log_mode != LOG_MODE_DIRTY_RING)
		continue;

		/*
		* For the dirty ring, empty the ring on subsequent
		* passes only if the ring was filled at least once,
		* to verify KVM's handling of a full ring (emptying
		* the ring on every pass would make it unlikely the
		* vCPU would ever fill the fing).
		*/
		if (i && !READ_ONCE(dirty_ring_vcpu_ring_full))
		continue;

		log_mode_collect_dirty_pages(vcpu, TEST_MEM_SLOT_INDEX,
		bmap, host_num_pages,
		bmap[0], host_num_pages,
		&ring_buf_idx);
		}

		/*
		* Stop the vCPU prior to collecting and verifying the dirty
		* log. If the vCPU is allowed to run during collection, then
		* pages that are written during this iteration may be missed,
		* i.e. collected in the next iteration. And if the vCPU is
		* writing memory during verification, pages that this thread
		* sees as clean may be written with this iteration's value.
		*/
		WRITE_ONCE(vcpu_stop, true);
		sync_global_to_guest(vm, vcpu_stop);
		sem_wait(&sem_vcpu_stop);

		/*
		* Clear vcpu_stop after the vCPU thread has acknowledge the
		* stop request and is waiting, i.e. is definitely not running!
		*/
		WRITE_ONCE(vcpu_stop, false);
		sync_global_to_guest(vm, vcpu_stop);

		/*
		* See vcpu_sync_stop_requested definition for details on why
		* we need to stop vcpu when verify data.
		* Sync the number of writes performed before verification, the
		* info will be printed along with the dirty/clean page counts.
		*/
		atomic_set(&vcpu_sync_stop_requested, true);
		sem_wait_until(&sem_vcpu_stop);
		sync_global_from_guest(vm, nr_writes);

		/*
		* NOTE: for dirty ring, it's possible that we didn't stop at
		* GUEST_SYNC but instead we stopped because ring is full;
		@@ -798,32 +787,22 @@ static void run_test(enum vm_guest_mode mode, void *arg)
		* the flush of the last page, and since we handle the last
		* page specially verification will succeed anyway.
		*/
		assert(host_log_mode == LOG_MODE_DIRTY_RING \|\|
		atomic_read(&vcpu_sync_stop_requested) == false);
		log_mode_collect_dirty_pages(vcpu, TEST_MEM_SLOT_INDEX,
		bmap[1], host_num_pages,
		&ring_buf_idx);
		vm_dirty_log_verify(mode, bmap);
		}

		/*
		* Set host_quit before sem_vcpu_cont in the final iteration to
		* ensure that the vCPU worker doesn't resume the guest. As
		* above, the dirty ring test may stop and wait even when not
		* explicitly request to do so, i.e. would hang waiting for a
		* "continue" if it's allowed to resume the guest.
		*/
		if (++iteration == p->iterations)
		WRITE_ONCE(host_quit, true);

		sem_post(&sem_vcpu_cont);
		sync_global_to_guest(vm, iteration);
		}

		pthread_join(vcpu_thread, NULL);

		pr_info("Total bits checked: dirty (%"PRIu64"), clear (%"PRIu64"), "
		"track_next (%"PRIu64")\n", host_dirty_count, host_clear_count,
		host_track_next_count);
		pr_info("Total bits checked: dirty (%lu), clear (%lu)\n",
		host_dirty_count, host_clear_count);

		free(bmap);
		free(host_bmap_track);
		free(bmap[0]);
		free(bmap[1]);
		kvm_vm_free(vm);
		}

		@@ -857,7 +836,6 @@ int main(int argc, char *argv[])
		.interval = TEST_HOST_LOOP_INTERVAL,
		};
		int opt, i;
		sigset_t sigset;

		sem_init(&sem_vcpu_stop, 0, 0);
		sem_init(&sem_vcpu_cont, 0, 0);
		@@ -908,19 +886,12 @@ int main(int argc, char *argv[])
		}
		}

		TEST_ASSERT(p.iterations > 2, "Iterations must be greater than two");
		TEST_ASSERT(p.iterations > 0, "Iterations must be greater than zero");
		TEST_ASSERT(p.interval > 0, "Interval must be greater than zero");

		pr_info("Test iterations: %"PRIu64", interval: %"PRIu64" (ms)\n",
		p.iterations, p.interval);

		srandom(time(0));

		/* Ensure that vCPU threads start with SIG_IPI blocked. */
		sigemptyset(&sigset);
		sigaddset(&sigset, SIG_IPI);
		pthread_sigmask(SIG_BLOCK, &sigset, NULL);

		if (host_log_mode_option == LOG_MODE_ALL) {
		/* Run each log mode */
		for (i = 0; i < LOG_MODE_NUM; i++) {

tools/testing/selftests/kvm/include/kvm_util.h

+21 −12

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tools/testing/selftests/kvm/include/x86/processor.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -200,6 +200,7 @@ struct kvm_x86_cpu_feature {
		#define X86_FEATURE_PAUSEFILTER KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 10)
		#define X86_FEATURE_PFTHRESHOLD KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 12)
		#define X86_FEATURE_VGIF KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 16)
		#define X86_FEATURE_IDLE_HLT KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 30)
		#define X86_FEATURE_SEV KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 1)
		#define X86_FEATURE_SEV_ES KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 3)
		#define X86_FEATURE_PERFMON_V2 KVM_X86_CPU_FEATURE(0x80000022, 0, EAX, 0)
		@@ -1251,7 +1252,7 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
		uint64_t ign_error_code; \
		uint8_t vector; \
		\
		asm volatile(KVM_ASM_SAFE(insn) \
		asm volatile(KVM_ASM_SAFE_FEP(insn) \
		: KVM_ASM_SAFE_OUTPUTS(vector, ign_error_code) \
		: inputs \
		: KVM_ASM_SAFE_CLOBBERS); \

tools/testing/selftests/kvm/kvm_create_max_vcpus.c

+1 −27

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tools/testing/selftests/kvm/lib/kvm_util.c

+80 −34

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