tree 428dc29ebd433849b621e6238e93e33f9cfca0e2
parent 6d0abeca3242a88cab8232e4acd7e2bf088f3bc2
author Marcelo Tosatti <mtosatti@redhat.com> 1393261172 -0300
committer Paolo Bonzini <pbonzini@redhat.com> 1393431812 +0100

KVM: MMU: drop read-only large sptes when creating lower level sptes

Read-only large sptes can be created due to read-only faults as
follows:

- QEMU pagetable entry that maps guest memory is read-only
due to COW.
- Guest read faults such memory, COW is not broken, because
it is a read-only fault.
- Enable dirty logging, large spte not nuked because it is read-only.
- Write-fault on such memory causes guest to loop endlessly
(which must go down to level 1 because dirty logging is enabled).

Fix by dropping large spte when necessary.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>