Messages in this thread | | | Date | Wed, 15 Sep 2010 10:48:33 +0200 | From | "Roedel, Joerg" <> | Subject | Re: [PATCH 2/2] KVM: MMU: Use base_role.nxe for mmu.nx |
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On Tue, Sep 14, 2010 at 06:08:37PM -0400, Marcelo Tosatti wrote: > > For tdp better set base_role.nxe to zero, otherwise duplicate tdp > pagetables can be created if the guest switches between nx/non-nx. >
This does not work because bit 63 is marked as reserved if base_role.nxe is 0. If the walk_addr_generic function then runs with tdp enabled it would report a set nx bit as a rsvd fault. We also can't use is_nx() in those path because it does not distinguish between l1 and l2 nx. Are there guests that switch the efer.nx bit regularly enough so that it matters? If so I would suggest to drop this patch and keep mmu.nx.
Joerg
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