pvh DOMU on NetBSD DOM0 crashes

[oskar%fessel.org@localhost]

Hej,

I ran into a problem with one of my NetBSD DomUs, it always hits the PVH domu with the highest index.

Message in the DOM0:
(XEN) p2m_pod_demand_populate: Dom5 out of PoD memory! (tot=131016 ents=131072 dom5)
(XEN) domain_crash called from arch/x86/mm/p2m-pod.c:1288
(XEN) Domain 5 (vcpu#0) crashed on cpu#0:
(XEN) ----[ Xen-4.18.0_20231116nb0  x86_64  debug=n  Not tainted ]----
(XEN) CPU:    0
(XEN) RIP:    0008:[<ffffffff8023439f>]
(XEN) RFLAGS: 0000000000010206   CONTEXT: hvm guest (d5v0)
(XEN) rax: 0000000000002800   rbx: 0000000000002800   rcx: 0000000000000200
(XEN) rdx: 00007c1cee2ba2c0   rsi: 00007c1cee2b92c0   rdi: ffffc10066592000
(XEN) rbp: ffffc100726f2c50   rsp: ffffc100726f2c08   r8:  00007f7ffffff000
(XEN) r9:  ffffc100726f2ca0   r10: 000000000000001b   r11: 0000000000000000
(XEN) r12: 0000000000002800   r13: ffffc10066590800   r14: ffffc100726f2ee0
(XEN) r15: ffffc100726f2ef0   cr0: 0000000080050033   cr4: 00000000001406b0
(XEN) cr3: 00000000047d6000   cr2: ffffc10066591000
(XEN) fsb: 00007c1cee327850   gsb: ffffffff8183cb00   gss: 0000000000000000
(XEN) ds: 0023   es: 0023   fs: 0000   gs: 0000   ss: 0010   cs: 0008
(XEN) p2m_pod_demand_populate: Dom5 out of PoD memory! (tot=131016 ents=131072 dom5)
(XEN) domain_crash called from arch/x86/mm/p2m-pod.c:1288
(XEN) p2m_pod_demand_populate: Dom5 out of PoD memory! (tot=131016 ents=131072 dom5)
(XEN) domain_crash called from arch/x86/mm/p2m-pod.c:1288
(XEN) p2m_pod_demand_populate: Dom5 out of PoD memory! (tot=131016 ents=131072 dom5)
(XEN) domain_crash called from arch/x86/mm/p2m-pod.c:1288

This is XEN 4.18, it happened also on 4.15.  I upgraded to 4.18 because of this ;-)

The config for this DOMU is:
——
type = pvh
name = "littlejoe"
boot = "c"
memory = 512
maxmem = 1024
vcpus = 1
vif = [ 'bridge=bridge1', 'bridge=bridge2' ]
kernel = "/netbsd-GENERIC.gz"
disk = [ '/hurz/joe/xendisklittlejoe,raw,xvda,rw‘ ]
——

all my pvh domUs run amd64
NetBSD 10.99.10 (GENERIC) #2: Fri Dec  8 23:45:08 CET 2023
the DOM0 itself is older:
NetBSD 10.99.2 (XEN3_DOM0) #0: Tue Dec 27 03:19:40 EET 2022 

The boot.cfg has the following entry:
menu=Boot Xen com:load /netbsd-XEN3_DOM0 root=dk6 console=com1,115200;multiboot /xen418.gz dom0_mem=32768M dom0_max_vcpus=8 console=com2 com2=115200,8n1,0x2f8

Anything missing there?

I switched most of my DOMUs from pv to pvh about 2 months ago, and 3 run flawless.  This is the only one running of file based backing store, the others run either on raw disks, or on zvols (which, btw. is annoyingly slow).

Can anyone point me to a way to fix this, short of switching back to pv?