Hi Jan, Roger and Andrew,

> -----Original Message-----
> From: Jan Beulich <jbeulich@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.Wang@arm.com>

Kind regards,
Henry

> 
> Jan

On 18.05.2022 11:51, Henry Wang wrote:
>> -----Original Message-----
>> From: Jan Beulich <jbeulich@suse.com>
>>
>> On 17.05.2022 17:31, Roger Pau Monne wrote:
>>> 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:

Well, no-one except you actually can ack changes to this file, as per
./MAINTAINERS.

> Acked-by: Henry Wang <Henry.Wang@arm.com>

Thanks.

Jan

Hi Jan,

> -----Original Message-----
> From: Jan Beulich <jbeulich@suse.com>
> 
> On 18.05.2022 11:51, Henry Wang wrote:
> >> -----Original Message-----
> >> From: Jan Beulich <jbeulich@suse.com>
> >>
> >> On 17.05.2022 17:31, Roger Pau Monne wrote:
> >>> 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:
> 
> Well, no-one except you actually can ack changes to this file, as per
> ./MAINTAINERS.

Thanks for confirming and sending the reminder to help me to understand
that I should ack the changes in CHANGELOG.md for this series, I will keep
the information in mind and I guess I am gradually acquiring experiences :)

Kind regards,
Henry

> 
> > Acked-by: Henry Wang <Henry.Wang@arm.com>
> 
> Thanks.
> 
> Jan