netbsd 9 adm64 HVM domU woes

[Greg Troxel <gdt%lexort.com@localhost>]

I have a xen dom0 running netbsd 9 amd64, which hangs.
I have other domUs running 9 i386, and 10 and current amd64 which do not hang.

xen disks are backed by zvols.
The hardware is about 1.5 years old and has been free of trouble.

xl top shows 'r'.

/var/log/messages inside the domU, after destroy/create shows

May 21 04:15:25 n9-amd64 /netbsd: [ 331049.5642390] autoconfiguration error: piixide0:0:0: lost interrupt
May 21 04:16:15 n9-amd64 /netbsd: [ 331049.5935340]     type: ata tc_bcount: 65536 tc_skip: 0
May 21 04:16:15 n9-amd64 /netbsd: [ 331049.7229220] autoconfiguration error: piixide0:0:0: bus-master DMA error: missing interrupt, status=0x61
May 21 04:16:15 n9-amd64 /netbsd: [ 331049.7270250] wd0a: DMA error writing fsbn 47108192 of 47108192-47108319 (wd0 bn 47108192; cn 23002 tn 0 sn 96), xfer 38, retry 0
May 21 04:16:15 n9-amd64 /netbsd: [ 331050.7374502] wd0: soft error (corrected) xfer 38
May 21 04:15:25 n9-amd64 mDNSResponder: mDNS_Execute,5348: mDNSPlatformRawTime went backwards by 46 ticks; setting correction factor to 1039618224
May 22 06:59:39 n9-amd64 syslogd[223]: restart
May 22 06:59:39 n9-amd64 /netbsd: [   1.0000000] Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,

Posted in case anyone has advice, or it helps someone else figure out
what's going on.

on the dom0

May 21 03:58:07 dom0 ntpd[1907]: Soliciting pool server 2607:7c80:54:3::32
May 21 03:58:08 dom0 ntpd[1907]: Soliciting pool server 2600:3c02::f03c:92ff:fe96:dc0
May 21 03:58:09 dom0 ntpd[1907]: Soliciting pool server 216.66.48.42
May 21 03:58:10 dom0 ntpd[1907]: Soliciting pool server 208.67.72.50
May 21 04:23:27 dom0 mDNSResponder: mDNSCoreReceive,10552: mDNSPlatformRawTime went backwards by 776 ticks; setting correction factor to 1841982830
May 21 04:24:25 dom0 mDNSResponder: mDNS_Execute,5348: mDNSPlatformRawTime went backwards by 687 ticks; setting correction factor to 1841983517

so interestingly some time complaints around the same time, but those
happen from time to time anyway.