On 07/05/2010 12:09 PM, Xiao Guangrong wrote:
Avi Kivity wrote:
I'm not convinced we can bypass the checks. Consider:
VCPU0 VCPU1
#PF
walk_addr
-> gpml4e0,gpdpe0,gpde0,gpte0
replace gpdpe0 with gpdpe1
#PF
walk_addr
-> gpml4e0,gpdpe1,gpde1,gpte1
fetch
-> establish hpml4e0,hpdpte1,hpde0,hpte1
fetch
read hpdpe1
if (present(hpdpe1))
continue;
...
write hpte0 using shadow hieratchy for hpte1
Ah, i missed this case, thanks for you point it out, i'll fix it in
the next version.
Note: I think we have to check _after_ kvm_mmu_get_page(), otherwise we
might be checking a page that is not write-protected and can change again.
So the logic needs to be something like
for_each_shadow_entry:
if (!last_level && !present(*spte))
kvm_mmu_get_page
verify gpte
if (last_level)
mmu_set_spte()
--
error compiling committee.c: too many arguments to function
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