[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH for-4.6] p2m/ept: Set the A bit only if PML is enabled
At 10:13 +0100 on 24 Sep (1443089607), Andrew Cooper wrote: > > >> etc along with adjusting the existing gating of PML on AD being > >> available (perhaps by simply stripping the respective bit from what > >> we read from MSR_IA32_VMX_EPT_VPID_CAP). Of course this > >> then ignores the fact that the erratum only affects the A bit, but > >> I think we can live with that. > >> > >> I also think the currently slightly strange setting of the ept_ad bit > >> should be changed: There's no point setting the bit for domains > >> not getting PML enabled (and incurring the overhead of the > >> hardware updating the bits); imo this should instead be done in > >> ept_enable_pml() / vmx_domain_enable_pml() (and undone in > >> the respective disable function). > > Yep. > > Just as a note, in the non PML case, the AD enable bit in EPTP is left > clear, which means that the A/D bits in the EPTs have no effect. I assumed the enable bit was what we were talking about -- the actual A/D bits in EPTEs should always be _set_ to avoid extra faults. So that sounds like we're already doing the right thing. Cheers, Tim. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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