PR/59618 CVS commit: [netbsd-11] src/sys/dev/pci

["Martin Husemann" <martin%netbsd.org@localhost>]

The following reply was made to PR kern/59618; it has been noted by GNATS.

From: "Martin Husemann" <martin%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/59618 CVS commit: [netbsd-11] src/sys/dev/pci
Date: Sun, 19 Oct 2025 13:53:08 +0000

 Module Name:	src
 Committed By:	martin
 Date:		Sun Oct 19 13:53:08 UTC 2025
 
 Modified Files:
 	src/sys/dev/pci [netbsd-11]: pvscsi.c
 
 Log Message:
 Pull up following revision(s) (requested by riastradh in ticket #64):
 
 	sys/dev/pci/pvscsi.c: revision 1.4
 	sys/dev/pci/pvscsi.c: revision 1.5
 
 pvscsi(4): Use bus_dmamap_sync, not membar_*, for DMA.
 membar_* may be a noop if we're booting on a single _virtual_ CPU,
 but the barriers are still needed in case the host behind pvscsi(4)
 is running on another _physical_ CPU.
 
 Prompted by (and related to but not the same issue as):
 PR kern/59618: occasional virtio block device lock ups/hangs
 
 pvscsi(4): Zero rings before using them.
 
 bus_dmamem_alloc(9) doesn't guarantee zeroing, as far as I can tell,
 and who knows what might happen if the ring header and contents have
 anything nonzero initially.
 
 Insert an initial preread/prewrite sync between zeroing and first
 use, and, out of paranoia, a final postread/postwrite sync between
 last use and unload/free.
 
 Prompted by (but not really related to):
 PR kern/59618: occasional virtio block device lock ups/hangs
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.2.2.3 -r1.2.2.4 src/sys/dev/pci/pvscsi.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.