KVM: MMU: nuke shadowed pgtable pages and ptes on memslot destruction

Flush the shadow mmu before removing regions to avoid stale entries.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

6 files changed, 20 insertions, 0 deletions

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 9408b30576d6..2672f4d278ac 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1455,6 +1455,9 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
         return 0;
 }
 
+void kvm_arch_flush_shadow(struct kvm *kvm)
+{
+}
 
 long kvm_arch_dev_ioctl(struct file *filp,
                 unsigned int ioctl, unsigned long arg)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index b850d2497027..53826a5f6c06 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -170,6 +170,10 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
         return 0;
 }
 
+void kvm_arch_flush_shadow(struct kvm *kvm)
+{
+}
+
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 {
         struct kvm_vcpu *vcpu;
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 399acf3f64dd..1782cbcd2829 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -675,6 +675,10 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
         return 0;
 }
 
+void kvm_arch_flush_shadow(struct kvm *kvm)
+{
+}
+
 gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
 {
         return gfn;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b131f3c0cf64..9f1cdb011cff 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4032,6 +4032,11 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
         return 0;
 }
 
+void kvm_arch_flush_shadow(struct kvm *kvm)
+{
+        kvm_mmu_zap_all(kvm);
+}
+
 int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
 {
         return vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d220b4926c4a..07d68a8ae8e9 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -168,6 +168,7 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
                                 struct kvm_userspace_memory_region *mem,
                                 struct kvm_memory_slot old,
                                 int user_alloc);
+void kvm_arch_flush_shadow(struct kvm *kvm);
 gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn);
 struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);
 unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 9ccaf8f5402e..30b36368fcdf 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -405,6 +405,9 @@ int __kvm_set_memory_region(struct kvm *kvm,
         if (mem->slot >= kvm->nmemslots)
                 kvm->nmemslots = mem->slot + 1;
 
+        if (!npages)
+                kvm_arch_flush_shadow(kvm);
+
         *memslot = new;
 
         r = kvm_arch_set_memory_region(kvm, mem, old, user_alloc);