Re: kern/60144: virtio(4) cache coherence issue

["Tetsuya Isaki via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR kern/60144; it has been noted by GNATS.

From: Tetsuya Isaki <isaki%pastel-flower.jp@localhost>
To: Taylor R Campbell <riastradh%NetBSD.org@localhost>
Cc: Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>,
	thorpej%me.com@localhost,
	nick.hudson%gmx.co.uk@localhost,
	gnats-bugs%netbsd.org@localhost,
	kern-bug-people%netbsd.org@localhost,
	netbsd-bugs%netbsd.org@localhost,
	adrian%NetBSD.org@localhost
Subject: Re: kern/60144: virtio(4) cache coherence issue
Date: Fri, 22 May 2026 13:48:30 +0900

 At Mon, 18 May 2026 23:29:58 +0000,
 Taylor R Campbell wrote:
 > OK, here is a candidate patch to address this issue.  Most of what
 > needs review is the commit message, but it would be good to test
 > whether it empirically addresses the problem too.  (Note that alone it
 > is probably _not_ enough to fix PR 60182, but it is probably needed
 > _in addition_ to the patch I already posted there.)
 > 
 > Isaki-san: Can you verify that this patch works?
 
 It worked with these three patches applied.  Thank you!
 - sys/arch/virt68k/virt68k/bus_dma.c,v 1.5 (I tested it on -11)
 - sys/dev/pci/ld_virtio.c (from kern/60182)
 - sys/dev/pci/virtio.c (this patch)
 
 By the way, one spurious interrupt has still occurred.
 
 ...
 virtio1: allocated 24576 byte for virtqueue 0 for I/O request, size 32
 virtio1: using 16384 byte (1024 entries) indirect descriptors
 virtio1: interrupting at gfpic4 irq 2 (IPL 5)
 ld1: 8192 MB, 4161 cyl, 64 head, 63 sec, 512 bytes/sect x 16777216 sectors (0 bytes/physsect)
 Spurious interrupt on CPU ipl 5
 No statclock; using hardclock.
 Initialzing hardclock: freq=100 Hz, interval=10000 usec
 timecounter: Timecounter "clockinterrupt" frequency 100 Hz quality 0
 swwdog0: software watchdog initialized
 root on ld0a dumps on ld0b
 root file system type: ffs
 ---
 Tetsuya Isaki <isaki%pastel-flower.jp@localhost / isaki%NetBSD.org@localhost>