Re: [Xen-devel] [PATCH for-4.6] p2m/ept: Set the A bit only if PML is enabled

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Thu, Sep 24, 2015 at 11:45:00AM +0100, Wei Liu wrote:
> On Thu, Sep 24, 2015 at 03:33:18AM -0600, Jan Beulich wrote:
> > >>> On 24.09.15 at 11:10, <tim@xxxxxxx> wrote:
> > > At 01:02 -0600 on 24 Sep (1443056566), Jan Beulich wrote:
> > >> --- a/xen/arch/x86/mm/p2m-ept.c
> > >> +++ b/xen/arch/x86/mm/p2m-ept.c
> > >> @@ -130,14 +130,18 @@ static void ept_p2m_type_to_flags(struct 
> > >> p2m_domain *p2m, ept_entry_t *entry,
> > >>              break;
> > >>          case p2m_ram_rw:
> > >>              entry->r = entry->w = entry->x = 1;
> > >> -            entry->a = entry->d = 1;
> > >> +            entry->a = entry->d = cpu_has_ept_ad;
> > >>              break;
> > >>          case p2m_mmio_direct:
> > >>              entry->r = entry->x = 1;
> > >>              entry->w = !rangeset_contains_singleton(mmio_ro_ranges,
> > >>                                                      entry->mfn);
> > >> -            entry->a = 1;
> > >> -            entry->d = entry->w;
> > >> +            entry->a = cpu_has_ept_ad;
> > >> +            entry->d = entry->w && cpu_has_ept_ad;
> > >>              break;
> > >>          case p2m_ram_logdirty:
> > >>              entry->r = entry->x = 1;
> > >> 
> > > 
> > > Sure, that works.  I still prefer putting the workaround on the CR3
> > > operation, so all the cost happens on the broken chip, but I'll shut
> > > up about that now. :)
> > 
> > And I agree to that for post-4.6. For 4.6 the easier to validate
> > fix still would seem to be a variation of what Ross posted.
> > 
> 
> I just finished this thread. Looks like HV maintainers have devised a
> plan for this issue.
> 
> Thank you all.

I forgot to mention should a patch appear please apply as you see fit.

Wei.

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