KVM: MMU: Segregate shadow pages with different cr0.wp
When cr0.wp=0, we may shadow a gpte having u/s=1 and r/w=0 with an spte having u/s=0 and r/w=1. This allows excessive access if the guest sets cr0.wp=1 and accesses through this spte. Fix by making cr0.wp part of the base role; we'll have different sptes for the two cases and the problem disappears. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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@@ -163,6 +163,8 @@ Shadow pages contain the following information:
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32-bit or 64-bit gptes are in use).
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role.cr4_nxe:
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Contains the value of efer.nxe for which the page is valid.
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role.cr0_wp:
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Contains the value of cr0.wp for which the page is valid.
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gfn:
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Either the guest page table containing the translations shadowed by this
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page, or the base page frame for linear translations. See role.direct.
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