Messages in this thread |  | | | Date | Fri, 2 Jul 2010 13:54:32 -0300 | | From | Marcelo Tosatti <> | | Subject | Re: [PATCH v4 4/6] KVM: MMU: prefetch ptes when intercepted guest #PF |
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On Thu, Jul 01, 2010 at 09:55:17PM +0800, Xiao Guangrong wrote: > Support prefetch ptes when intercept guest #PF, avoid to #PF by later > access > > If we meet any failure in the prefetch path, we will exit it and > not try other ptes to avoid become heavy path > > Note: this speculative will mark page become dirty but it not really > accessed, the same issue is in other speculative paths like invlpg, > pte write, fortunately, it just affect host memory management. After > Avi's patchset named "[PATCH v2 1/4] KVM: MMU: Introduce drop_spte()" > merged, we will easily fix it. Will do it in the future. > > Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> > --- > arch/x86/kvm/mmu.c | 79 ++++++++++++++++++++++++++++++++++++++++++++ > arch/x86/kvm/paging_tmpl.h | 76 ++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 155 insertions(+), 0 deletions(-) >
> + if (pte_prefetch_topup_memory_cache(vcpu)) > + return; > + > + for (j = 0; i < max; i++, j++) { > + pt_element_t gpte; > + unsigned pte_access; > + u64 *spte = sp->spt + i; > + gfn_t gfn; > + pfn_t pfn; > + > + if (spte == sptep) > + continue; > + > + if (*spte != shadow_trap_nonpresent_pte) > + continue; > + > + gpte = gptep[j]; > + > + if (is_rsvd_bits_set(vcpu, gpte, PT_PAGE_TABLE_LEVEL)) > + break;
BTW, doesnt sync_page also lack reserved bit checking? (unrelated to this patch).
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