@@ -17,6 +17,7 @@
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <asm/barrier.h>
+#include <linux/atomic.h>
#include "kvm_util.h"
#include "test_util.h"
@@ -137,12 +138,20 @@ static uint64_t host_clear_count;
static uint64_t host_track_next_count;
/* Whether dirty ring reset is requested, or finished */
-static sem_t dirty_ring_vcpu_stop;
-static sem_t dirty_ring_vcpu_cont;
+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
- * dirty_ring_vcpu_stop and before vcpu continues to run.
+ * sem_vcpu_stop and before vcpu continues to run.
*/
static bool dirty_ring_vcpu_ring_full;
/*
@@ -234,6 +243,17 @@ static void clear_log_collect_dirty_page
kvm_vm_clear_dirty_log(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_vm *vm, int ret, int err)
{
struct kvm_run *run = vcpu_state(vm, VCPU_ID);
@@ -244,6 +264,8 @@ static void default_after_vcpu_run(struc
TEST_ASSERT(get_ucall(vm, VCPU_ID, 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)
@@ -301,13 +323,13 @@ static void dirty_ring_wait_vcpu(void)
{
/* This makes sure that hardware PML cache flushed */
vcpu_kick();
- sem_wait_until(&dirty_ring_vcpu_stop);
+ sem_wait_until(&sem_vcpu_stop);
}
static void dirty_ring_continue_vcpu(void)
{
pr_info("Notifying vcpu to continue\n");
- sem_post(&dirty_ring_vcpu_cont);
+ sem_post(&sem_vcpu_cont);
}
static void dirty_ring_collect_dirty_pages(struct kvm_vm *vm, int slot,
@@ -361,11 +383,11 @@ static void dirty_ring_after_vcpu_run(st
/* Update the flag first before pause */
WRITE_ONCE(dirty_ring_vcpu_ring_full,
run->exit_reason == KVM_EXIT_DIRTY_RING_FULL);
- sem_post(&dirty_ring_vcpu_stop);
+ 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(&dirty_ring_vcpu_cont);
+ sem_wait_until(&sem_vcpu_cont);
pr_info("vcpu continues now.\n");
} else {
TEST_ASSERT(false, "Invalid guest sync status: "
@@ -377,7 +399,7 @@ static void dirty_ring_after_vcpu_run(st
static void dirty_ring_before_vcpu_join(void)
{
/* Kick another round of vcpu just to make sure it will quit */
- sem_post(&dirty_ring_vcpu_cont);
+ sem_post(&sem_vcpu_cont);
}
struct log_mode {
@@ -768,7 +790,25 @@ static void run_test(enum vm_guest_mode
usleep(p->interval * 1000);
log_mode_collect_dirty_pages(vm, 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);
}
@@ -819,8 +859,8 @@ int main(int argc, char *argv[])
};
int opt, i;
- sem_init(&dirty_ring_vcpu_stop, 0, 0);
- sem_init(&dirty_ring_vcpu_cont, 0, 0);
+ sem_init(&sem_vcpu_stop, 0, 0);
+ sem_init(&sem_vcpu_cont, 0, 0);
guest_modes_append_default();