Messages in this thread | | | Subject | Re: [PATCH 1/2] KVM: MMU: fix ept=0/pte.u=0/pte.w=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 combo | From | Xiao Guangrong <> | Date | Thu, 10 Mar 2016 16:46:12 +0800 |
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On 03/08/2016 07:44 PM, Paolo Bonzini wrote: > Yes, all of these are needed. :) This is admittedly a bit odd, but > kvm-unit-tests access.flat tests this if you run it with "-cpu host" > and of course ept=0. > > KVM handles supervisor writes of a pte.u=0/pte.w=0/CR0.WP=0 page by > setting U=0 and W=1 in the shadow PTE. This will cause a user write > to fault and a supervisor write to succeed (which is correct because > CR0.WP=0). A user read instead will flip U=0 to 1 and W=1 back to 0.
BTW, it should be pte.u = 1 where you mentioned above.
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