MFC 259737, 262646:

Fix a couple of issues with vcpu state:
- Add a parameter to 'vcpu_set_state()' to enforce that the vcpu is in the
  IDLE state before the requested state transition. This guarantees that
  there is exactly one ioctl() operating on a vcpu at any point in time and
  prevents unintended state transitions.
- Fix a race between VMRUN() and vcpu_notify_event() due to 'vcpu->hostcpu'
  being updated outside of the vcpu_lock().

1 files changed, 2 insertions, 13 deletions

diff --git a/usr.sbin/bhyve/bhyverun.c b/usr.sbin/bhyve/bhyverun.c
index c1bc0d2..5cde323 100644
--- a/usr.sbin/bhyve/bhyverun.c
+++ b/usr.sbin/bhyve/bhyverun.c
@@ -493,19 +493,8 @@ vm_loop(struct vmctx *ctx, int vcpu, uint64_t rip)
 
 	while (1) {
 		error = vm_run(ctx, vcpu, rip, &vmexit[vcpu]);
-		if (error != 0) {
-			/*
-			 * It is possible that 'vmmctl' or some other process
-			 * has transitioned the vcpu to CANNOT_RUN state right
-			 * before we tried to transition it to RUNNING.
-			 *
-			 * This is expected to be temporary so just retry.
-			 */
-			if (errno == EBUSY)
-				continue;
-			else
-				break;
-		}
+		if (error != 0)
+			break;
 
 		prevcpu = vcpu;