Pull up following revision(s) (requested by riastradh in ticket NetBSD#63):

	sys/dev/pci/pvscsi.c: revision 1.3

pvscsi(4): Use paravirt_membar_sync(9) where needed.

PR kern/59618: occasional virtio block device lock ups/hangs
(pvscsi(4) is not virtio(4) but the same fundamental issue arises.)

Author: MartinHusemann

sys/dev/pci/pvscsi.c

@@ -59,7 +59,7 @@ in the file called LICENSE.GPL.
 */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pvscsi.c,v 1.2.2.2 2025/08/08 14:19:54 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pvscsi.c,v 1.2.2.3 2025/10/19 11:09:18 martin Exp $");
 
 #include <sys/param.h>
 
@@ -70,6 +70,7 @@ __KERNEL_RCSID(0, "$NetBSD: pvscsi.c,v 1.2.2.2 2025/08/08 14:19:54 martin Exp $"
 #include <sys/device.h>
 #include <sys/kernel.h>
 #include <sys/kmem.h>
+#include <sys/paravirt_membar.h>
 #include <sys/queue.h>
 #include <sys/sysctl.h>
 #include <sys/systm.h>
@@ -380,6 +381,12 @@ pvscsi_kick_io(struct pvscsi_softc *sc, uint8_t cdb0)
 	    cdb0 == WRITE_12 || cdb0 == WRITE_16) {
 		s = sc->rings_state;
 
+		/*
+		 * Ensure the command has been published before we test
+		 * whether we need to kick the host.
+		 */
+		paravirt_membar_sync();
+
 		DEBUG_PRINTF(2, sc->dev, "%s req prod %d cons %d\n", __func__,
 		    s->req_prod_idx, s->req_cons_idx);
 		if (!sc->use_req_call_threshold ||