On 20/04/21 15:10, Peter Xu wrote:
On Tue, Apr 20, 2021 at 10:07:16AM +0200, Paolo Bonzini wrote:
On 18/04/21 14:43, Peter Xu wrote:
----8<-----
diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
index 25230e799bc4..d3050d1c2cd0 100644
--- a/tools/testing/selftests/kvm/dirty_log_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -377,7 +377,7 @@ static void dirty_ring_after_vcpu_run(struct kvm_vm *vm, int ret, int err)
/* A ucall-sync or ring-full event is allowed */
if (get_ucall(vm, VCPU_ID, NULL) == UCALL_SYNC) {
/* We should allow this to continue */
- ;
+ vcpu_handle_sync_stop();
} else if (run->exit_reason == KVM_EXIT_DIRTY_RING_FULL ||
(ret == -1 && err == EINTR)) {
/* Update the flag first before pause */
----8<-----
That's my intention when I introduce vcpu_handle_sync_stop(), but forgot to
add...
And possibly even this (untested though):
diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
index ffa4e2791926..918954f01cef 100644
--- a/tools/testing/selftests/kvm/dirty_log_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -383,6 +383,7 @@ static void dirty_ring_after_vcpu_run(struct kvm_vm *vm, int ret, int err)
/* Update the flag first before pause */
WRITE_ONCE(dirty_ring_vcpu_ring_full,
run->exit_reason == KVM_EXIT_DIRTY_RING_FULL);
+ atomic_set(&vcpu_sync_stop_requested, false);
sem_post(&sem_vcpu_stop);
pr_info("vcpu stops because %s...\n",
dirty_ring_vcpu_ring_full ?
@@ -804,8 +805,7 @@ 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);
+ assert(atomic_read(&vcpu_sync_stop_requested) == false);
vm_dirty_log_verify(mode, bmap);
sem_post(&sem_vcpu_cont);
You can submit all these as a separate patch.
But it could race, then?
main thread vcpu thread
----------- -----------
ring full
vcpu_sync_stop_requested=0
sem_post(&sem_vcpu_stop)
vcpu_sync_stop_requested=1
sem_wait(&sem_vcpu_stop)
assert(vcpu_sync_stop_requested==0) <----
Yes, it could indeed.
Thanks,
Paolo
