From e49146dce8c3dc6f4485c1904b6587855f393e71 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Wed, 22 Dec 2010 09:01:57 -0200 Subject: [PATCH] KVM: MMU: only write protect mappings at pagetable level If a pagetable contains a writeable large spte, all of its sptes will be 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. Tested-by: Alex Williamson Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/mmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index b77a5ba398be..a2127f82e786 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3445,6 +3445,9 @@ 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 */