diff mbox

[PULL,01/10] virtio: hide legacy features from modern guests

Message ID 1438077261-16651-2-git-send-email-mst@redhat.com
State New
Headers show

Commit Message

Michael S. Tsirkin July 28, 2015, 9:57 a.m. UTC 
NOTIFY_ON_EMPTY, ANY_LAYOUT and BAD are only valid on the legacy
interface.

Hide them from modern guests.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/hw/virtio/virtio.h | 4 ++++
 hw/virtio/virtio-pci.c     | 3 ++-
 2 files changed, 6 insertions(+), 1 deletion(-)
diff mbox

Patch

diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 473fb75..0634c15 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -25,6 +25,10 @@ 
 /* A guest should never accept this.  It implies negotiation is broken. */
 #define VIRTIO_F_BAD_FEATURE		30
 
+#define VIRTIO_LEGACY_FEATURES ((0x1ULL << VIRTIO_F_BAD_FEATURE) | \
+                                (0x1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | \
+                                (0x1ULL << VIRTIO_F_ANY_LAYOUT))
+
 struct VirtQueue;
 
 static inline hwaddr vring_align(hwaddr addr,
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 283401a..db8f27c 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1095,7 +1095,8 @@  static uint64_t virtio_pci_common_read(void *opaque, hwaddr addr,
         break;
     case VIRTIO_PCI_COMMON_DF:
         if (proxy->dfselect <= 1) {
-            val = vdev->host_features >> (32 * proxy->dfselect);
+            val = (vdev->host_features & ~VIRTIO_LEGACY_FEATURES) >>
+                (32 * proxy->dfselect);
         }
         break;
     case VIRTIO_PCI_COMMON_GFSELECT: