KVM: set_memory_region: Disallow changing read-only attribute later

As Xiao pointed out, there are a few problems with it:
 - kvm_arch_commit_memory_region() write protects the memory slot only
   for GET_DIRTY_LOG when modifying the flags.
 - FNAME(sync_page) uses the old spte value to set a new one without
   checking KVM_MEM_READONLY flag.

Since we flush all shadow pages when creating a new slot, the simplest
fix is to disallow such problematic flag changes: this is safe because
no one is doing such things.

Reviewed-by: Gleb Natapov <[email protected]>
Signed-off-by: Takuya Yoshikawa <[email protected]>
Cc: Xiao Guangrong <[email protected]>
Cc: Alex Williamson <[email protected]>
Signed-off-by: Marcelo Tosatti <[email protected]>

0 files changed, 0 insertions, 0 deletions