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[Qemu-devel] [PATCH] virtio: hide legacy features from modern guests
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PATCH] virtio: hide legacy features from modern guests |
Date: |
Wed, 22 Jul 2015 13:11:35 +0300 |
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 <address@hidden>
---
include/hw/virtio/virtio.h | 4 ++++
hw/virtio/virtio-pci.c | 3 ++-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index fbb3c06..cbe3a5a 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:
--
MST
- [Qemu-devel] [PATCH] virtio: hide legacy features from modern guests,
Michael S. Tsirkin <=