Mailing List Archive

Problems with APIC on versions 4.9 and later (4.8 works)
Hi,

Sorry for the simultaneous post on xen-users and xen-devel, but as I noted
that the problem appears only for versions of xen that are >= 4.9, I think
that developers may have a look at this.

I recently bought a generic mainboard and a Xeon E5-2926v2 CPU, it is a 12
core, 24 threads cpu.

My system was already running on another machine with xen 4.11 on a debian
10 system and after replacing the mainboard it didn't boot.

After many tries I noticed that downgrading to the previous version of Xen
(4.8, available on Debian 9) works well. I also tried a lot of variations
for the dom0 kernel, all of them with the same results.

All my tests were done with 4.11, but I checked with a live version of
Alpine Linux (3.7.3, with Xen 4.9.4) that the system doesn't boot on that
release also.

With more research I noticed that if I limit dom0 to use only one CPU
(dom0_max_vcpus=1) the system boots up, I didn't check if guest VM worked,
but I suppose that they would not be able to use the other 23 vcpus
available, anyway, a system with one vcpu for dom0 would be very slow I
think.

I've noticed also that if I keep dom0 to use more than one core but disable
acpi on the dom0 kernel, it boots up, unfortunately this is not
sufficient because I cannot use any device attached to the system (not even
the usb keyboard). This only helps to detect that the problem may be in the
ACPI/APIC code.

I tried many variations with parameters related with ACPI and APIC. None of
them was satisfactory, always ended on a halted system or a self rebooting
one.

Can anyone point me to a solution for this?

Best regards,
Claudemir