Messages in this thread |  | | | Date | Tue, 13 Jul 2010 08:35:33 +0300 | | From | Avi Kivity <> | | Subject | Re: [PATCH v5 6/9] KVM: MMU: introduce pte_prefetch_topup_memory_cache() |
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On 07/13/2010 07:25 AM, Xiao Guangrong wrote: > >> Regressions? no. Or do you mean the problem already exists? Where? >> > I mean this is a exist problem, likes invlpg, pte-write and sync-page, there are > speculative path that it's not real access, but marked dirty if pte is writable. >
Right. We should fix those too.
Prefetch is much more worrying though, especially with ept. If a guest is using just 1/8 of the pages, it can look to migration as if it's using 100% of the pages. The impact can be pretty large.
In contrast, I'm not too worried about invlpg, as most times an access will follow a miss, and usually a write access if we set a writeable pte. Not sure about sync-page.
-- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.
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