KVM: MMU: invalidate and flush on spte small->large page size change

Always invalidate spte and flush TLBs when changing page size, to make sure different sized translations for the same address are never cached in a CPU's TLB. Currently the only case where this occurs is when a non-leaf spte pointer is overwritten by a leaf, large spte entry. This can happen after dirty logging is disabled on a memslot, for example. Noticed by Andrea. KVM-Stable-Tag Signed-off-by: Marcelo Tosatti <[email protected]> Signed-off-by: Avi Kivity <[email protected]>
Findingmyway · Jun 9, 2010 · 3be2264 · 3be2264
1 parent 67ec660
commit 3be2264
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
@@ -1870,6 +1870,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 
 			child = page_header(pte & PT64_BASE_ADDR_MASK);
 			mmu_page_remove_parent_pte(child, sptep);
+			__set_spte(sptep, shadow_trap_nonpresent_pte);
+			kvm_flush_remote_tlbs(vcpu->kvm);
 		} else if (pfn != spte_to_pfn(*sptep)) {
 			pgprintk("hfn old %lx new %lx\n",
 				 spte_to_pfn(*sptep), pfn);