On Fri, 20 Mar 2026 at 09:50, Mohamed Mediouni <[email protected]> wrote:
>
>
> > On 20. Mar 2026, at 10:17, Peter Maydell <[email protected]> wrote:
> >
> > On Thu, 19 Mar 2026 at 18:50, Mohamed Mediouni <[email protected]> 
> > wrote:
> >>
> >>
> >>> On 19. Mar 2026, at 19:13, Peter Maydell <[email protected]> wrote:
> >>>
> >>> On Sat, 14 Mar 2026 at 22:15, Mohamed Mediouni <[email protected]> 
> >>> wrote:
> >>>>
> >>>> Linux uses AccessVpRegs without checking availability and panics if it's 
> >>>> not there. Expose it unconditionally.
> >>>
> >>> The commit message subject says we're enabling enlightenments...
> >>>
> >>>> @@ -953,13 +953,15 @@ int whpx_accel_init(AccelState *as, MachineState 
> >>>> *ms)
> >>>>    synthetic_features.Bank0.AccessPartitionReferenceTsc = 1;
> >>>>    synthetic_features.Bank0.AccessHypercallRegs = 1;
> >>>>    synthetic_features.Bank0.AccessVpIndex = 1;
> >>>> -    synthetic_features.Bank0.AccessHypercallRegs = 1;
> >>>
> >>> ...but the code change seems to be removing one as well as
> >>> adding the three new ones. Intentional?
> >> Hello,
> >>
> >> The AccessHypercallRegs bit was set twice - with the first one being two
> >> lines earlier - removed a spurious one of the two.
> >
> > Ah, right. How about this for a commit message ?
> >
> >
> >    whpx: arm: enable more enlightenments
> >
> >    Unconditionally enable some more enlightenments for whpx. In
> >    particular, linux uses AccessVpRegs without checking availability and
> >    panics if it's not there, so it's important to expose it.
> >
> >    We also had a duplicate line where we set AccessHypercallRegs = 1
> >    twice; remove the duplicate.
> >
> >
> > If you have more rationale/info about the other two we're enabling,
> > that would also be nice to include.

> ```
> whpx: arm: enable more enlightenments
>
> Enable some more enlightenments for whpx for -accel whpx,hyperv=on.
> In particular, Linux uses AccessVpRegs without checking availability when
> Hyper-V enlightenments are exposed and panics if it's not there.
>
> We also had a duplicate line where we set AccessHypercallRegs = 1
> twice; remove the duplicate.
>
> Microsoft’s VMM exposes SyncContext on arm64 and FastHypercallOutput
> regardless of architecture unconditionally, so add those two to match
> that configuration.
>
> ```

Thanks -- I've updated the commit message for this patch in
target-arm.next to that.

-- PMM

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