Re: KVM: MMU: nuke shadowed pgtable pages and pte's on memslot destruction

[Marcelo Tosatti <mtosatti@redhat.com>]

On Thu, Jul 10, 2008 at 01:58:24PM -0500, Hollis Blanchard wrote:
> > This (and its friends) ought to be static inlines.
> > 
> > On the other hand, don't the other arches have to flush their tlbs?  
> > Xiantao/Hollis?  So maybe this function needs to be renamed 
> > kvm_flush_shadow() and implemented across the board.
> 
> Agreed, I think that's the right approach.

Ok, here it is, Hollis and Xiantao can you fill in the blanks?

----------

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

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index a4cf4a2..d10e35b 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1455,6 +1455,10 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
 	return 0;
 }
 
+void kvm_arch_flush_shadow(struct kvm *kvm)
+{
+	return;
+}
 
 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 b850d24..2c438a7 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -170,6 +170,11 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
 	return 0;
 }
 
+void kvm_arch_flush_shadow(struct kvm *kvm)
+{
+	return;
+}
+
 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 399acf3..5612c00 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -675,6 +675,11 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
 	return 0;
 }
 
+void kvm_arch_flush_shadow(struct kvm *kvm)
+{
+	return;
+}
+
 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 c9b8a04..dedb581 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4040,6 +4040,11 @@ 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 fc685c5..3798097 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 b90da0b..c459383 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);