Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 927 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
new file mode 100644
index 000000000..b5234d6ef
--- /dev/null
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -0,0 +1,927 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KVM dirty page logging test
+ *
+ * Copyright (C) 2018, Red Hat, Inc.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_name */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <errno.h>
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/atomic.h>
+#include <asm/barrier.h>
+
+#include "kvm_util.h"
+#include "test_util.h"
+#include "guest_modes.h"
+#include "processor.h"
+
+/* The memory slot index to track dirty pages */
+#define TEST_MEM_SLOT_INDEX		1
+
+/* 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
+
+/* 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)
+# define test_bit_le(nr, addr) \
+	test_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
+# define set_bit_le(nr, addr) \
+	set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
+# define clear_bit_le(nr, addr) \
+	clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
+# define test_and_set_bit_le(nr, addr) \
+	test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
+# define test_and_clear_bit_le(nr, addr) \
+	test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
+#else
+# define test_bit_le		test_bit
+# define set_bit_le		set_bit
+# define clear_bit_le		clear_bit
+# define test_and_set_bit_le	test_and_set_bit
+# define test_and_clear_bit_le	test_and_clear_bit
+#endif
+
+#define TEST_DIRTY_RING_COUNT		65536
+
+#define SIG_IPI SIGUSR1
+
+/*
+ * Guest/Host shared variables. Ensure addr_gva2hva() and/or
+ * sync_global_to/from_guest() are used when accessing from
+ * the host. READ/WRITE_ONCE() should also be used with anything
+ * that may change.
+ */
+static uint64_t host_page_size;
+static uint64_t guest_page_size;
+static uint64_t guest_num_pages;
+static uint64_t random_array[TEST_PAGES_PER_LOOP];
+static uint64_t iteration;
+
+/*
+ * Guest physical memory offset of the testing memory slot.
+ * This will be set to the topmost valid physical address minus
+ * the test memory size.
+ */
+static uint64_t guest_test_phys_mem;
+
+/*
+ * Guest virtual memory offset of the testing memory slot.
+ * Must not conflict with identity mapped test code.
+ */
+static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
+
+/*
+ * Continuously write to the first 8 bytes of a random pages within
+ * the testing memory region.
+ */
+static void guest_code(void)
+{
+	uint64_t addr;
+	int i;
+
+	/*
+	 * On s390x, all pages of a 1M segment are initially marked as dirty
+	 * when a page of the segment is written to for the very first time.
+	 * To compensate this specialty in this test, we need to touch all
+	 * pages during the first iteration.
+	 */
+	for (i = 0; i < guest_num_pages; i++) {
+		addr = guest_test_virt_mem + i * guest_page_size;
+		*(uint64_t *)addr = READ_ONCE(iteration);
+	}
+
+	while (true) {
+		for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
+			addr = guest_test_virt_mem;
+			addr += (READ_ONCE(random_array[i]) % guest_num_pages)
+				* guest_page_size;
+			addr = align_down(addr, host_page_size);
+			*(uint64_t *)addr = READ_ONCE(iteration);
+		}
+
+		/* Tell the host that we need more random numbers */
+		GUEST_SYNC(1);
+	}
+}
+
+/* Host variables */
+static bool host_quit;
+
+/* Points to the test VM memory region on which we track dirty logs */
+static void *host_test_mem;
+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
+ * ring full.  When that happens, the very last PFN is set but actually the
+ * data is not changed (the guest WRITE is not really applied yet), because
+ * we found that the dirty ring is full, refused to continue the vcpu, and
+ * recorded the dirty gfn with the old contents.
+ *
+ * For this specific case, it's safe to skip checking this pfn for this
+ * bit, because it's a redundant bit, and when the write happens later the bit
+ * will be set again.  We use this variable to always keep track of the latest
+ * 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;
+
+enum log_mode_t {
+	/* Only use KVM_GET_DIRTY_LOG for logging */
+	LOG_MODE_DIRTY_LOG = 0,
+
+	/* Use both KVM_[GET|CLEAR]_DIRTY_LOG for logging */
+	LOG_MODE_CLEAR_LOG = 1,
+
+	/* Use dirty ring for logging */
+	LOG_MODE_DIRTY_RING = 2,
+
+	LOG_MODE_NUM,
+
+	/* Run all supported modes */
+	LOG_MODE_ALL = LOG_MODE_NUM,
+};
+
+/* Mode of logging to test.  Default is to run all supported modes */
+static enum log_mode_t host_log_mode_option = LOG_MODE_ALL;
+/* Logging mode for current run */
+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);
+}
+
+static void clear_log_create_vm_done(struct kvm_vm *vm)
+{
+	u64 manual_caps;
+
+	manual_caps = kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
+	TEST_ASSERT(manual_caps, "MANUAL_CAPS is zero!");
+	manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
+			KVM_DIRTY_LOG_INITIALLY_SET);
+	vm_enable_cap(vm, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, manual_caps);
+}
+
+static void dirty_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
+					  void *bitmap, uint32_t num_pages)
+{
+	kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap);
+}
+
+static void clear_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
+					  void *bitmap, uint32_t num_pages)
+{
+	kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap);
+	kvm_vm_clear_dirty_log(vcpu->vm, slot, bitmap, 0, num_pages);
+}
+
+/* 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);
+		sem_post(&sem_vcpu_stop);
+		sem_wait_until(&sem_vcpu_cont);
+	}
+}
+
+static void default_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
+{
+	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\n",
+		    exit_reason_str(run->exit_reason));
+
+	vcpu_handle_sync_stop();
+}
+
+static bool dirty_ring_supported(void)
+{
+	return (kvm_has_cap(KVM_CAP_DIRTY_LOG_RING) ||
+		kvm_has_cap(KVM_CAP_DIRTY_LOG_RING_ACQ_REL));
+}
+
+static void dirty_ring_create_vm_done(struct kvm_vm *vm)
+{
+	/*
+	 * Switch to dirty ring mode after VM creation but before any
+	 * of the vcpu creation.
+	 */
+	vm_enable_dirty_ring(vm, test_dirty_ring_count *
+			     sizeof(struct kvm_dirty_gfn));
+}
+
+static inline bool dirty_gfn_is_dirtied(struct kvm_dirty_gfn *gfn)
+{
+	return smp_load_acquire(&gfn->flags) == KVM_DIRTY_GFN_F_DIRTY;
+}
+
+static inline void dirty_gfn_set_collected(struct kvm_dirty_gfn *gfn)
+{
+	smp_store_release(&gfn->flags, KVM_DIRTY_GFN_F_RESET);
+}
+
+static uint32_t dirty_ring_collect_one(struct kvm_dirty_gfn *dirty_gfns,
+				       int slot, void *bitmap,
+				       uint32_t num_pages, uint32_t *fetch_index)
+{
+	struct kvm_dirty_gfn *cur;
+	uint32_t count = 0;
+
+	while (true) {
+		cur = &dirty_gfns[*fetch_index % test_dirty_ring_count];
+		if (!dirty_gfn_is_dirtied(cur))
+			break;
+		TEST_ASSERT(cur->slot == slot, "Slot number didn't match: "
+			    "%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);
+		(*fetch_index)++;
+		count++;
+	}
+
+	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)
+{
+	/* We only have one vcpu */
+	static uint32_t fetch_index = 0;
+	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;
+	}
+
+	/* Only have one vcpu */
+	count = dirty_ring_collect_one(vcpu_map_dirty_ring(vcpu),
+				       slot, bitmap, num_pages, &fetch_index);
+
+	cleared = kvm_vm_reset_dirty_ring(vcpu->vm);
+
+	/* Cleared pages should be the same as collected */
+	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)
+{
+	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");
+	} else {
+		TEST_ASSERT(false, "Invalid guest sync status: "
+			    "exit_reason=%s\n",
+			    exit_reason_str(run->exit_reason));
+	}
+}
+
+static void dirty_ring_before_vcpu_join(void)
+{
+	/* Kick another round of vcpu just to make sure it will quit */
+	sem_post(&sem_vcpu_cont);
+}
+
+struct log_mode {
+	const char *name;
+	/* Return true if this mode is supported, otherwise false */
+	bool (*supported)(void);
+	/* Hook when the vm creation is done (before vcpu creation) */
+	void (*create_vm_done)(struct kvm_vm *vm);
+	/* Hook to collect the dirty pages into the bitmap provided */
+	void (*collect_dirty_pages) (struct kvm_vcpu *vcpu, int slot,
+				     void *bitmap, uint32_t num_pages);
+	/* Hook to call when after each vcpu run */
+	void (*after_vcpu_run)(struct kvm_vcpu *vcpu, int ret, int err);
+	void (*before_vcpu_join) (void);
+} log_modes[LOG_MODE_NUM] = {
+	{
+		.name = "dirty-log",
+		.collect_dirty_pages = dirty_log_collect_dirty_pages,
+		.after_vcpu_run = default_after_vcpu_run,
+	},
+	{
+		.name = "clear-log",
+		.supported = clear_log_supported,
+		.create_vm_done = clear_log_create_vm_done,
+		.collect_dirty_pages = clear_log_collect_dirty_pages,
+		.after_vcpu_run = default_after_vcpu_run,
+	},
+	{
+		.name = "dirty-ring",
+		.supported = dirty_ring_supported,
+		.create_vm_done = dirty_ring_create_vm_done,
+		.collect_dirty_pages = dirty_ring_collect_dirty_pages,
+		.before_vcpu_join = dirty_ring_before_vcpu_join,
+		.after_vcpu_run = dirty_ring_after_vcpu_run,
+	},
+};
+
+/*
+ * 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;
+
+	printf("all");
+	for (i = 0; i < LOG_MODE_NUM; i++)
+		printf(", %s", log_modes[i].name);
+	printf("\n");
+}
+
+static bool log_mode_supported(void)
+{
+	struct log_mode *mode = &log_modes[host_log_mode];
+
+	if (mode->supported)
+		return mode->supported();
+
+	return true;
+}
+
+static void log_mode_create_vm_done(struct kvm_vm *vm)
+{
+	struct log_mode *mode = &log_modes[host_log_mode];
+
+	if (mode->create_vm_done)
+		mode->create_vm_done(vm);
+}
+
+static void log_mode_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot,
+					 void *bitmap, uint32_t num_pages)
+{
+	struct log_mode *mode = &log_modes[host_log_mode];
+
+	TEST_ASSERT(mode->collect_dirty_pages != NULL,
+		    "collect_dirty_pages() is required for any log mode!");
+	mode->collect_dirty_pages(vcpu, slot, bitmap, num_pages);
+}
+
+static void log_mode_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
+{
+	struct log_mode *mode = &log_modes[host_log_mode];
+
+	if (mode->after_vcpu_run)
+		mode->after_vcpu_run(vcpu, ret, err);
+}
+
+static void log_mode_before_vcpu_join(void)
+{
+	struct log_mode *mode = &log_modes[host_log_mode];
+
+	if (mode->before_vcpu_join)
+		mode->before_vcpu_join();
+}
+
+static void generate_random_array(uint64_t *guest_array, uint64_t size)
+{
+	uint64_t i;
+
+	for (i = 0; i < size; i++)
+		guest_array[i] = random();
+}
+
+static void *vcpu_worker(void *data)
+{
+	int ret;
+	struct kvm_vcpu *vcpu = data;
+	struct kvm_vm *vm = vcpu->vm;
+	uint64_t *guest_array;
+	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);
+
+	guest_array = addr_gva2hva(vm, (vm_vaddr_t)random_array);
+
+	while (!READ_ONCE(host_quit)) {
+		/* Clear any existing kick signals */
+		generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
+		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);
+		}
+		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)
+{
+	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);
+		}
+
+		if (test_and_clear_bit_le(page, bmap)) {
+			bool matched;
+
+			host_dirty_count++;
+
+			/*
+			 * If the bit is set, the value written onto
+			 * the corresponding page should be either the
+			 * previous iteration number or the current one.
+			 */
+			matched = (*value_ptr == iteration ||
+				   *value_ptr == iteration - 1);
+
+			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.
+					 */
+					min_iter = iteration - 1;
+					continue;
+				} else if (page == dirty_ring_last_page) {
+					/*
+					 * Please refer to comments in
+					 * dirty_ring_last_page.
+					 */
+					continue;
+				}
+			}
+
+			TEST_ASSERT(matched,
+				    "Set page %"PRIu64" value %"PRIu64
+				    " incorrect (iteration=%"PRIu64")",
+				    page, *value_ptr, iteration);
+		} else {
+			host_clear_count++;
+			/*
+			 * 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
+				 */
+				set_bit_le(page, host_bmap_track);
+			}
+		}
+	}
+}
+
+static struct kvm_vm *create_vm(enum vm_guest_mode mode, struct kvm_vcpu **vcpu,
+				uint64_t extra_mem_pages, void *guest_code)
+{
+	struct kvm_vm *vm;
+
+	pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
+
+	vm = __vm_create(mode, 1, extra_mem_pages);
+
+	log_mode_create_vm_done(vm);
+	*vcpu = vm_vcpu_add(vm, 0, guest_code);
+	return vm;
+}
+
+#define DIRTY_MEM_BITS 30 /* 1G */
+#define PAGE_SHIFT_4K  12
+
+struct test_params {
+	unsigned long iterations;
+	unsigned long interval;
+	uint64_t phys_offset;
+};
+
+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;
+
+	if (!log_mode_supported()) {
+		print_skip("Log mode '%s' not supported",
+			   log_modes[host_log_mode].name);
+		return;
+	}
+
+	/*
+	 * We reserve page table for 2 times of extra dirty mem which
+	 * will definitely cover the original (1G+) test range.  Here
+	 * we do the calculation with 4K page size which is the
+	 * smallest so the page number will be enough for all archs
+	 * (e.g., 64K page size guest will need even less memory for
+	 * page tables).
+	 */
+	vm = create_vm(mode, &vcpu,
+		       2ul << (DIRTY_MEM_BITS - PAGE_SHIFT_4K), guest_code);
+
+	guest_page_size = vm->page_size;
+	/*
+	 * A little more than 1G of guest page sized pages.  Cover the
+	 * case where the size is not aligned to 64 pages.
+	 */
+	guest_num_pages = (1ul << (DIRTY_MEM_BITS - vm->page_shift)) + 3;
+	guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
+
+	host_page_size = getpagesize();
+	host_num_pages = vm_num_host_pages(mode, guest_num_pages);
+
+	if (!p->phys_offset) {
+		guest_test_phys_mem = (vm->max_gfn - guest_num_pages) *
+				      guest_page_size;
+		guest_test_phys_mem = align_down(guest_test_phys_mem, host_page_size);
+	} else {
+		guest_test_phys_mem = p->phys_offset;
+	}
+
+#ifdef __s390x__
+	/* Align to 1M (segment size) */
+	guest_test_phys_mem = align_down(guest_test_phys_mem, 1 << 20);
+#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);
+
+	/* Add an extra memory slot for testing dirty logging */
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+				    guest_test_phys_mem,
+				    TEST_MEM_SLOT_INDEX,
+				    guest_num_pages,
+				    KVM_MEM_LOG_DIRTY_PAGES);
+
+	/* Do mapping for the dirty track memory slot */
+	virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages);
+
+	/* Cache the HVA pointer of the region */
+	host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);
+
+	ucall_init(vm, NULL);
+
+	/* Export the shared variables to the guest */
+	sync_global_to_guest(vm, host_page_size);
+	sync_global_to_guest(vm, guest_page_size);
+	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);
+	host_quit = false;
+	host_dirty_count = 0;
+	host_clear_count = 0;
+	host_track_next_count = 0;
+
+	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);
+		log_mode_collect_dirty_pages(vcpu, TEST_MEM_SLOT_INDEX,
+					     bmap, host_num_pages);
+
+		/*
+		 * See vcpu_sync_stop_requested definition for details on why
+		 * we need to stop vcpu when verify data.
+		 */
+		atomic_set(&vcpu_sync_stop_requested, true);
+		sem_wait_until(&sem_vcpu_stop);
+		/*
+		 * NOTE: for dirty ring, it's possible that we didn't stop at
+		 * GUEST_SYNC but instead we stopped because ring is full;
+		 * that's okay too because ring full means we're only missing
+		 * 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);
+		vm_dirty_log_verify(mode, bmap);
+		sem_post(&sem_vcpu_cont);
+
+		iteration++;
+		sync_global_to_guest(vm, iteration);
+	}
+
+	/* Tell the vcpu thread to quit */
+	host_quit = true;
+	log_mode_before_vcpu_join();
+	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);
+
+	free(bmap);
+	free(host_bmap_track);
+	ucall_uninit(vm);
+	kvm_vm_free(vm);
+}
+
+static void help(char *name)
+{
+	puts("");
+	printf("usage: %s [-h] [-i iterations] [-I interval] "
+	       "[-p offset] [-m mode]\n", name);
+	puts("");
+	printf(" -c: specify dirty ring size, in number of entries\n");
+	printf("     (only useful for dirty-ring test; default: %"PRIu32")\n",
+	       TEST_DIRTY_RING_COUNT);
+	printf(" -i: specify iteration counts (default: %"PRIu64")\n",
+	       TEST_HOST_LOOP_N);
+	printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
+	       TEST_HOST_LOOP_INTERVAL);
+	printf(" -p: specify guest physical test memory offset\n"
+	       "     Warning: a low offset can conflict with the loaded test code.\n");
+	printf(" -M: specify the host logging mode "
+	       "(default: run all log modes).  Supported modes: \n\t");
+	log_modes_dump();
+	guest_modes_help();
+	puts("");
+	exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+	struct test_params p = {
+		.iterations = TEST_HOST_LOOP_N,
+		.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);
+
+	guest_modes_append_default();
+
+	while ((opt = getopt(argc, argv, "c:hi:I:p:m:M:")) != -1) {
+		switch (opt) {
+		case 'c':
+			test_dirty_ring_count = strtol(optarg, NULL, 10);
+			break;
+		case 'i':
+			p.iterations = strtol(optarg, NULL, 10);
+			break;
+		case 'I':
+			p.interval = strtol(optarg, NULL, 10);
+			break;
+		case 'p':
+			p.phys_offset = strtoull(optarg, NULL, 0);
+			break;
+		case 'm':
+			guest_modes_cmdline(optarg);
+			break;
+		case 'M':
+			if (!strcmp(optarg, "all")) {
+				host_log_mode_option = LOG_MODE_ALL;
+				break;
+			}
+			for (i = 0; i < LOG_MODE_NUM; i++) {
+				if (!strcmp(optarg, log_modes[i].name)) {
+					pr_info("Setting log mode to: '%s'\n",
+						optarg);
+					host_log_mode_option = i;
+					break;
+				}
+			}
+			if (i == LOG_MODE_NUM) {
+				printf("Log mode '%s' invalid. Please choose "
+				       "from: ", optarg);
+				log_modes_dump();
+				exit(1);
+			}
+			break;
+		case 'h':
+		default:
+			help(argv[0]);
+			break;
+		}
+	}
+
+	TEST_ASSERT(p.iterations > 2, "Iterations must be greater than two");
+	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++) {
+			pr_info("Testing Log Mode '%s'\n", log_modes[i].name);
+			host_log_mode = i;
+			for_each_guest_mode(run_test, &p);
+		}
+	} else {
+		host_log_mode = host_log_mode_option;
+		for_each_guest_mode(run_test, &p);
+	}
+
+	return 0;
+}