Re: [Xen-devel] [PATCH for-4.13 v2] x86/vlapic: allow setting APIC_SPIV_FOCUS_DISABLED in x2APIC mode

[Jürgen Groß <jgross@xxxxxxxx>]

On 21.11.19 11:19, Roger Pau Monne wrote:
> Current code unconditionally prevents setting APIC_SPIV_FOCUS_DISABLED
> regardless of the processor model, which is not correct according to
> the specification.
>
> This issue was discovered while trying to boot a pvshim with x2APIC
> enabled.
>
> Always allow setting APIC_SPIV_FOCUS_DISABLED: the local APIC
> provided to guests is emulated by Xen, and as such doesn't depend on
> the features found on the hardware processor. Note for example that
> Xen offers x2APIC support to guests even when the underlying hardware
> doesn't have such feature.
>
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Release-acked-by: Juergen Gross <jgross@xxxxxxxx>


Juergen

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