CVS commit: src/sys/dev/pci

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Sat Sep  6 02:56:52 UTC 2025

Modified Files:
        src/sys/dev/pci: pvscsi.c

Log Message:
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 -r1.4 -r1.5 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.