Re: VCPUOP_send_nmi returns -38

On Tue, Jan 11, 2022 at 12:28:01PM +0200, Andriy Gapon wrote:
> On 11/01/2022 12:26, Roger Pau Monné wrote:
> > On Tue, Jan 11, 2022 at 12:07:28PM +0200, Andriy Gapon wrote:
> > > On 11/01/2022 11:50, Andriy Gapon wrote:
> > > > 
> > > > Recently I got a report of crashes related to using procstat -k on one
> > > > of our systems.  The system runs FreeBSD 12.2 on an AWS Xen-based
> > > > instance (can get more specifics about it later).
> > > 
> > > The instance type is t2.large.
> > > Here are all lines from verbose boot that mention Xen:
> > > 
> > > XEN: Hypervisor version 4.2 detected.
> > > Disabling MSI-X interrupt migration due to Xen hypervisor bug.
> > > XEN: disabling emulated disks
> > > XEN: disabling emulated nics
> > > Hypervisor: Origin = "XenVMMXenVMM"
> > > x2APIC available but disabled due to running under XEN
> > 
> > Thanks. I've asked someone at AWS for comments. I guess the only way
> > to workaround this is to switch back to using the emulated APIC. I
> > will try to prepare a patch later.
> 
> Thank you very much!

I've got two patches for you to try, the first one is 'mni-fix.patch'
and should fix the NMI sending issue.

I'm also attaching a second patch, that should allow your guest to use
x2APIC. FreeBSD has previously prevented Xen guests from using x2APIC
because of a bug in old Xen versions, but I think this should be
solved now, so if FreeBSD can successfully boot on your VM with the
patch applied I think we are safe to enable x2APIC. That one is called
'x2apic.patch'.

Let me know how the testing goes.

Thanks, Roger.