KVM: Drop user return notifier when disabling virtualization on a cpu
This way, we don't leave a dangling notifier on cpu hotunplug or module
unload. In particular, module unload leaves the notifier pointing into
freed memory.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 35eea30..106f9f1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -201,6 +201,14 @@
}
EXPORT_SYMBOL_GPL(kvm_set_shared_msr);
+static void drop_user_return_notifiers(void *ignore)
+{
+ struct kvm_shared_msrs *smsr = &__get_cpu_var(shared_msrs);
+
+ if (smsr->registered)
+ kvm_on_user_return(&smsr->urn);
+}
+
unsigned long segment_base(u16 selector)
{
struct descriptor_table gdt;
@@ -5004,6 +5012,7 @@
void kvm_arch_hardware_disable(void *garbage)
{
kvm_x86_ops->hardware_disable(garbage);
+ drop_user_return_notifiers(garbage);
}
int kvm_arch_hardware_setup(void)