Re: Xen 4.16 development update - tree status

[Andrew Cooper <amc96@xxxxxxxx>]

On 19/11/2021 15:15, Ian Jackson wrote:
> Open issues and potential blockers
> ==================================
>
> I am aware of three issues for which I don't know the current
> disposition:
>
> * "x86/IOMMU: enabled / intremap handling"
>   3/3 "AMD/IOMMU: iommu_enable vs iommu_intremap"
>   Last I heard this was being reworked.

Some of this has been committed, and has fixed the regression I reported.

One part is quite risky, and not a regression fix (Xen has been broken
for years and years here).  I suggest deferring that part to 4.17.

I'm not aware of further actions required on this task for 4.16.

> * I have a note "HPET regression".  There have been number of patches in
>   this area.  Most recently,
>   "x86/hpet: setup HPET even when disabled due to stopping in deep C states"

This regression has been fixed too.  The bugfix got in ahead of RC1.

> * "x86/viridian: EOI MSR should always happen in affected vCPU context"
>   Jan mentioned this on IRC but I don't see any discussion of it in
>   my mailbox.
>
> The last two were mentioned in my last release update, but I don't
> seem to find any definitive conclusion.  x86 maintainers, can you
> please confirm ?

There is not consensus on whether the change is correct, although I
admit it had fallen off my radar.

All it is doing is introducing two ASSERT_UNREACHABLE()'s.  It's not
critical for 4.16 at this point.

~Andrew