>>> On 27.11.18 at 15:19, <andrew.coop...@citrix.com> wrote: > On 27/11/2018 13:06, Jan Beulich wrote: >>>>> On 26.11.18 at 18:30, <paul.durr...@citrix.com> wrote: >>> The page merging logic makes use of bits 1-8 and bit 63 of a PTE, which used >>> to be specified as ignored. However, bits 5 and 6 are now specified as >>> 'accessed' and 'dirty' bits and their use only remains safe as long as >>> the DTE 'Host Access Dirty' bits remain clear. >> Upon second thought - is this actually true with the XSA-275 >> changes in place? As long as the domain is not running yet, >> how would A and/or D bits get set? > > DTE.HAD is an IOMMU control which Xen doesn't currently enable, so this > isn't an issue in current usage.
Well, of course, and Paul did say so. My point is that even when we start using the feature, as long as we don't set A and/or D bits ourselves, nothing is getting in the way of the merging code, as it ceases to do anything once the domain starts running. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
