On 12/22/2010 01:01 PM, Marcelo Tosatti wrote:
If a pagetable contains a writeable large spte, all of its sptes will be
non-writeable
write protected, including non-leaf ones, leading to endless pagefaults. Do not write protect pages above PT_PAGE_TABLE_LEVEL, as the spte fault paths assume non-leaf sptes are writable. Signed-off-by: Marcelo Tosatti<mtosatti@xxxxxxxxxx> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index c3853d5..c716ff8 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3442,6 +3442,9 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) if (!test_bit(slot, sp->slot_bitmap)) continue; + if (sp->role.level != PT_PAGE_TABLE_LEVEL) + continue; + pt = sp->spt; for (i = 0; i< PT64_ENT_PER_PAGE; ++i) /* avoid RMW */
But what about large leaf sptes? Don't we want to write protect, or perhaps drop them?
I think write-protecting leaf sptes and ignoring nonleaf sptes should work. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
