KVM: MMU: ignore zapped root pagetables

Mark zapped root pagetables as invalid and ignore such pages during lookup.

This is a problem with the cr3-target feature, where a zapped root table fools
the faulting code into creating a read-only mapping. The result is a lockup
if the instruction can't be emulated.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

2 files changed, 3 insertions, 0 deletions

diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 935ffa4db9f4..8c3f74b73524 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -141,6 +141,7 @@ union kvm_mmu_page_role {
                 unsigned pad_for_nice_hex_output:6;
                 unsigned metaphysical:1;
                 unsigned access:3;
+                unsigned invalid:1;
         };
 };
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index eb88d32dd5c7..994278fb5883 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -37,6 +37,7 @@
 #define KVM_REQ_TLB_FLUSH          0
 #define KVM_REQ_MIGRATE_TIMER      1
 #define KVM_REQ_REPORT_TPR_ACCESS  2
+#define KVM_REQ_MMU_RELOAD         3
 
 struct kvm_vcpu;
 extern struct kmem_cache *kvm_vcpu_cache;
@@ -190,6 +191,7 @@ void kvm_resched(struct kvm_vcpu *vcpu);
 void kvm_load_guest_fpu(struct kvm_vcpu *vcpu);
 void kvm_put_guest_fpu(struct kvm_vcpu *vcpu);
 void kvm_flush_remote_tlbs(struct kvm *kvm);
+void kvm_reload_remote_mmus(struct kvm *kvm);
 
 long kvm_arch_dev_ioctl(struct file *filp,
                         unsigned int ioctl, unsigned long arg);