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>
diff --git a/Documentation/kvm/mmu.txt b/Documentation/kvm/mmu.txt
index 0cc28fb..aaed6ab 100644
--- a/Documentation/kvm/mmu.txt
+++ b/Documentation/kvm/mmu.txt
@@ -163,6 +163,8 @@
32-bit or 64-bit gptes are in use).
role.cr4_nxe:
Contains the value of efer.nxe for which the page is valid.
+ role.cr0_wp:
+ Contains the value of cr0.wp for which the page is valid.
gfn:
Either the guest page table containing the translations shadowed by this
page, or the base page frame for linear translations. See role.direct.