KVM: Advertise the bug in memory region destruction as fixed

Userspace might need to act differently.

Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 14 insertions, 1 deletions

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 0997e6f5490c..48807767e726 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -395,6 +395,8 @@ struct kvm_trace_rec {
 #if defined(CONFIG_X86)
 #define KVM_CAP_DEVICE_MSI 20
 #endif
+/* Bug in KVM_SET_USER_MEMORY_REGION fixed: */
+#define KVM_CAP_DESTROY_MEMORY_REGION_WORKS 21
 
 /*
  * ioctls for VM fds
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e7644b90667e..e066eb125e55 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1905,6 +1905,17 @@ static int kvm_dev_ioctl_create_vm(void)
         return fd;
 }
 
+static long kvm_dev_ioctl_check_extension_generic(long arg)
+{
+        switch (arg) {
+        case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
+                return 1;
+        default:
+                break;
+        }
+        return kvm_dev_ioctl_check_extension(arg);
+}
+
 static long kvm_dev_ioctl(struct file *filp,
                           unsigned int ioctl, unsigned long arg)
 {
@@ -1924,7 +1935,7 @@ static long kvm_dev_ioctl(struct file *filp,
                 r = kvm_dev_ioctl_create_vm();
                 break;
         case KVM_CHECK_EXTENSION:
-                r = kvm_dev_ioctl_check_extension(arg);
+                r = kvm_dev_ioctl_check_extension_generic(arg);
                 break;
         case KVM_GET_VCPU_MMAP_SIZE:
                 r = -EINVAL;