kern/57002: Starting NetBSD in a HVM DomU crashes Dom0

[Hauke Fath <hf%spg.tu-darmstadt.de@localhost>]

>Number:         57002
>Category:       kern
>Synopsis:       Starting NetBSD in a HVM DomU crashes Dom0
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Sep 09 17:05:00 +0000 2022
>Originator:     Hauke Fath
>Release:        NetBSD 9.3
>Organization:
Technische Universitaet Darmstadt
>Environment:
	
	
System: NetBSD Treffauer 9.3 NetBSD 9.3 (FEUERKOGEL_DOM0-$Revision$) #0: Tue Aug 9 15:30:14 CEST 2022 hf@Hochstuhl:/var/obj/netbsd-builds/9/amd64/sys/arch/amd64/compile/FEUERKOGEL_DOM0 amd64
Architecture: x86_64
Machine: amd64
% pkg_info | grep xen
xenkernel413-4.13.4nb1 Xen 4.13.x Kernel
xentools413-4.13.4nb6 Userland Tools for Xen 4.13.x
%

>Description:

	Starting a Xen HVM DomU from a NetBSD 9 install iso crashes
	the Dom0 with

[...]
[ 296.6180677] xbd backend: attach device vg0-hazel_root (size 20971520) for domain 2
[ 300.3380380] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0c00107000 did not change!
[ 334.8277708] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0c00151000 did not change!
[ 334.8277708] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0c00152000 did not change!
[ 334.8277708] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0c00153000 did not change!
[ 337.3877490] pmap_unwire: wiring for pmap 0xffffb48004fcf060 va 0x7c0bf5dfc000 did not change!
[ 337.3877490] panic: kernel diagnostic assertion "pg->wire_count != 0" failed: file "/u/netbsd-9/src/sys/uvm/uvm_page.c", line 1618 
[ 337.3877490] cpu0: Begin traceback...
[ 337.3977488] vpanic() at netbsd:vpanic+0x143
[ 337.3977488] kern_assert() at netbsd:kern_assert+0x48
[ 337.3977488] uvm_pageunwire() at netbsd:uvm_pageunwire+0x81
[ 337.3977488] uvm_fault_unwire_locked() at netbsd:uvm_fault_unwire_locked+0x135
[ 337.3977488] uvm_fault_unwire() at netbsd:uvm_fault_unwire+0x29
[ 337.3977488] physio_done() at netbsd:physio_done+0x77
[ 337.3977488] workqueue_worker() at netbsd:workqueue_worker+0xce
[ 337.3977488] cpu0: End traceback...

[ 337.3977488] dumping to dev 18,1 (offset=33554431, size=0): not possible
[ 337.3977488] rebooting...
(XEN) Hardware Dom0 shutdown: rebooting machine
(XEN) Resetting with ACPI MEMORY or I/O RESET_REG.[-- hf@localhost detached -- Fri Sep  9 18:44:46 2022]


	
>How-To-Repeat:
	

	Set up a Xen DomU HVM configuration with an lvm disk device and a
	NetBSD 9 iso image. Have it render to VNC.

	Watch the boot freeze while probing the disk device, then
	watch the Xen host crash and reboot.

	The DomU configuration is

type = "hvm"
firmware = "seabios"
kernel = "/usr/pkg/libexec/xen/boot/hvmloader"
memory = 1024
vcpus = 1
acpi = 1
name = "Hazel"
ioemu = [ 'mac=00:16:3e:NN:MM:OO, bridge=bridge1' ]
disk = [ 'backendtype=phy, vdev=hda, target=/dev/mapper/vg0-hazel_root',
         'vdev=hdb, devtype=cdrom, target=/var/tmp/NetBSD-9.0_STABLE-amd64.iso']
vga="cirrus"
vnc=1
vnclisten="127.0.0.1"
vncdisplay=10
serial = "pty"

>Fix:
	
	Yes, please.

>Unformatted: