Messages in this thread | | | Date | Sat, 21 Apr 2012 12:29:44 +0800 | From | Xiao Guangrong <> | Subject | Re: [PATCH v3 5/9] KVM: MMU: introduce SPTE_WRITE_PROTECT bit |
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On 04/21/2012 08:55 AM, Marcelo Tosatti wrote:
>> So this is an example of implicit assumptions which break if you update >> spte without mmu_lock. Certainly there are more cases. :( > > OK, i now see you mentioned a similar case in the document, for > rmap_write_protect. > > More importantly than the particular flush TLB case, the point is > every piece of code that reads and writes sptes must now be aware that > mmu_lock alone does not guarantee stability. Everything must be audited. >
Yes, that is true, but it is not hard to audit the code since we only change the spte from read-only to writable, also all information that fast page fault depends on is from spte.
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