KVM: MMU: Push clean gpte write protection out of gpte_access()

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gpte_access() computes the access permissions of a guest pte and also
write-protects clean gptes.  This is wrong when we are servicing a
write fault (since we'll be setting the dirty bit momentarily) but
correct when instantiating a speculative spte, or when servicing a
read fault (since we'll want to trap a following write in order to
set the dirty bit).

It doesn't seem to hurt in practice, but in order to make the code
readable, push the write protection out of gpte_access() and into
a new protect_clean_gpte() which is called explicitly when needed.

Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

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This commit is contained in:

Avi Kivity 2012-09-12 13:44:53 +03:00

parent 879238fecc

commit 8ea667f259

3 changed files with 26 additions and 13 deletions

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12

arch/x86/kvm/mmu.c

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3

arch/x86/kvm/mmu.h

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24

arch/x86/kvm/paging_tmpl.h

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