Re: [PATCH v2 3/10] KVM: MMU: fix direct sp's access corruptted

From: Avi Kivity
Date: Tue Jun 29 2010 - 05:13:40 EST

On 06/29/2010 12:04 PM, Xiao Guangrong wrote:

Simply replace (*spte& SPTE_NO_DIRTY) with a condition that checks
whether sp->access is consistent with gw->pt(e)_access.

If the guest mapping is writable and it !dirty, we mark SPTE_NO_DIRTY flag in
the spte, when the next #PF occurs, we just need check this flag and see whether
gpte's D bit is set, if it's true, we zap this spte and map to the correct sp.

My point is, SPTE_NO_DIRTY is equivalent to an sp->role.access check (the access check is a bit slower, but that shouldn't matter).

Can you write a test case for qemu-kvm.git/kvm/test that demonstrates
the problem and the fix? It will help ensure we don't regress in this

OK, but allow me do it later :-)

Sure, but please do it soon.

error compiling committee.c: too many arguments to function

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