On Wed, Oct 23, 2013 at 09:29:21PM +0800, Xiao Guangrong wrote: > 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 > > Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx> Reviewed-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
