From 7f31c9595e3c87f68dc54b3269e900f3017ed405 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Thu, 17 Apr 2014 17:06:15 +0800 Subject: [PATCH] KVM: MMU: flush tlb if the spte can be locklessly modified Relax the tlb flush condition since we will write-protect the spte out of mmu lock. Note lockless write-protection only marks the writable spte to readonly and the spte can be writable only if both SPTE_HOST_WRITEABLE and SPTE_MMU_WRITEABLE are set (that are tested by spte_is_locklessly_modifiable) This patch is used to avoid this kind of race: VCPU 0 VCPU 1 lockless wirte protection: set spte.w = 0 lock mmu-lock write protection the spte to sync shadow page, see spte.w = 0, then without flush tlb unlock mmu-lock !!! At this point, the shadow page can still be writable due to the corrupt tlb entry Flush all TLB Reviewed-by: Marcelo Tosatti Signed-off-by: Xiao Guangrong Signed-off-by: Marcelo Tosatti --- Reading git-format-patch failed