On Thu, Nov 17, 2022 at 10:27:41AM +0100, Jan Beulich wrote:
> On 16.11.2022 17:42, Roger Pau Monne wrote:
> > Currently Xen will passthrough any Local APIC NMI Structure found in
> > the native ACPI MADT table to a PVH dom0. This is wrong because PVH
> > doesn't have access to the physical local APIC, and instead gets an
> > emulated local APIC by Xen, that doesn't have the LINT0 or LINT1
> > pins wired to anything. Furthermore the ACPI Processor UIDs used in
> > the APIC NMI Structures are likely to not match the ones generated by
> > Xen for the Local x2APIC Structures, creating confusion to dom0.
>
> Plus we should have passed through Local x2APIC NMI Structures then as
> well.
Sadly this is not possible for PVH dom0, Linux will use the ACPI
Processor UID as vCPU ID in hypercalls, so if the UIDs don't start at
0 and are sequential Linux will panic during boot because vCPU
operations will fail.
> > Fix this by removing the logic to passthrough the Local APIC NMI
> > Structure for PVH dom0.
> >
> > Fixes: 1d74282c45 ('x86: setup PVHv2 Dom0 ACPI tables')
> > Signed-off-by: Roger Pau Monné <[email protected]>
>
> Reviewed-by: Jan Beulich <[email protected]>
> albeit with the implied ack in there provisional upon Andrew accepting
> your response to his reply.
Thanks, Roger.
