On Fri, Apr 29, 2022 at 10:12:01AM +0100, Joao Martins wrote:
> On 4/29/22 03:26, Jason Wang wrote:
> > On Fri, Apr 29, 2022 at 5:14 AM Joao Martins <joao.m.martins@xxxxxxxxxx> wrote:
> >> @@ -3693,7 +3759,8 @@ static void vtd_init(IntelIOMMUState *s)
> >>
> >> /* TODO: read cap/ecap from host to decide which cap to be exposed. */
> >> if (s->scalable_mode) {
> >> - s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_SRS | VTD_ECAP_SLTS;
> >> + s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_SRS | VTD_ECAP_SLTS |
> >> + VTD_ECAP_SLADS;
> >> }
> >
> > We probably need a dedicated command line parameter and make it compat
> > for pre 7.1 machines.
> >
> > Otherwise we may break migration.
>
> I can gate over an 'x-ssads' option (default disabled). Which reminds me that I probably
> should rename to the most recent mnemonic (as SLADS no longer exists in manuals).
>
> If we all want by default enabled I can add a separate patch to do so.
The new option sounds good.
Jason, per our previous discussion, shall we not worry about the
compatibility issues per machine-type until the whole feature reaches a
mostly-complete stage?
There seems to have a bunch of sub-features for scalable mode and it's a
large project as a whole. I'm worried trying to maintain compatibilities
for all the small sub-features could be an unnessary burden to the code
base.
Thanks,
--
Peter Xu
