Re: [PATCH v5] KVM x86/xen: add an override for PVCLOCK_TSC_STABLE_BIT

[Paul Durrant]

On 08/11/2023 18:39, David Woodhouse wrote:
> On Thu, 2023-11-02 at 16:21 +0000, Paul Durrant wrote:
> > From: Paul Durrant <pdurrant@xxxxxxxxxx>
> >
> > Unless explicitly told to do so (by passing 'clocksource=tsc' and
> > 'tsc=stable:socket', and then jumping through some hoops concerning
> > potential CPU hotplug) Xen will never use TSC as its clocksource.
> > Hence, by default, a Xen guest will not see PVCLOCK_TSC_STABLE_BIT set
> > in either the primary or secondary pvclock memory areas. This has
> > led to bugs in some guest kernels which only become evident if
> > PVCLOCK_TSC_STABLE_BIT *is* set in the pvclocks. Hence, to support
> > such guests, give the VMM a new Xen HVM config flag to tell KVM to
> > forcibly clear the bit in the Xen pvclocks.
> >
> > Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
>
> Reviewed-by: David Woodhouse <dwmw@xxxxxxxxxxxx>

Sean,

  Is any more work needed on this?

  Paul