Hi Jan, Roger and Andrew,
> -----Original Message-----
> From: Jan Beulich <jbeul...@suse.com>
>
> On 17.05.2022 17:31, Roger Pau Monne wrote:
> > Hello,
> >
> > The following series implements support for MSR_VIRT_SPEC_CTRL
> > (VIRT_SSBD) on different AMD CPU families.
> >
> > Note that the support is added backwards, starting with the newer CPUs
> > that support MSR_SPEC_CTRL and moving to the older ones either using
> > MSR_VIRT_SPEC_CTRL or the SSBD bit in LS_CFG.
> >
> > Xen is still free to use it's own SSBD setting, as the selection is
> > context switched on vm{entry,exit}.
> >
> > On Zen2 and later, SPEC_CTRL.SSBD should exist and should be used in
> > preference to VIRT_SPEC_CTRL.SSBD. However, for migration
> > compatibility, Xen offers VIRT_SSBD to guests (in the max cpuid policy,
> > not default) implemented in terms of SPEC_CTRL.SSBD.
> >
> > On Fam15h thru Zen1, Xen exposes VIRT_SSBD to guests by default to
> > abstract away the model and/or hypervisor specific differences in
> > MSR_LS_CFG/MSR_VIRT_SPEC_CTRL.
> >
> > So the implementation of VIRT_SSBD exposed to HVM guests will use one
> of
> > the following underlying mechanisms, in the preference order listed
> > below:
> >
> > * SPEC_CTRL.SSBD: patch 1
> > * VIRT_SPEC_CTRL.SSBD: patch 2.
> > * Non-architectural way using LS_CFG: patch 3.
> >
> > NB: patch 3 introduces some logic in GIF=0 context, such logic has been
> > kept to a minimum due to the special context it's running on.
> >
> > Roger Pau Monne (3):
> > amd/msr: implement VIRT_SPEC_CTRL for HVM guests on top of
> SPEC_CTRL
> > amd/msr: allow passthrough of VIRT_SPEC_CTRL for HVM guests
> > amd/msr: implement VIRT_SPEC_CTRL for HVM guests using legacy SSBD
>
> FTAOD, while besides a missing ack for ...
>
> > CHANGELOG.md | 3 +
>
> ... this addition the series would now look to be ready to go in,
> I'd like to have some form of confirmation by you, Andrew, that
> you now view this as meeting the comments you gave on an earlier
> version.
Not completely sure if I am proper to do that but for the CHANGELOG.md
change:
Acked-by: Henry Wang <henry.w...@arm.com>
Kind regards,
Henry
>
> Jan
