Hi Jason,
Pls see my comments inline marked by GD>>
Regards,
Gautam
-----Original Message-----
From: Jason Wang <jasow...@redhat.com>
Sent: Wednesday, June 2, 2021 9:01 AM
To: m...@redhat.com; qemu-devel@nongnu.org
Cc: Gautam Dawar <gda...@xilinx.com>; l...@redhat.com; Jason Wang
<jasow...@redhat.com>; qemu-sta...@nongnu.org
Subject: [PATCH 1/2] vhost-vdpa: don't initialize backend_features
We used to initialize backend_features during vhost_vdpa_init() regardless
whether or not it was supported by vhost. This will lead the unsupported
features like VIRTIO_F_IN_ORDER to be included and set to the vhost-vdpa during
vhost_dev_start. Because the VIRTIO_F_IN_ORDER is not supported by vhost-vdpa
so it won't be advertised to guest which will break the datapath.
Fix this by not initializing the backend_features, so the acked_features could
be built only from guest features via vhost_net_ack_features().
Fixes: 108a64818e69b ("vhost-vdpa: introduce vhost-vdpa backend")
Cc: qemu-sta...@nongnu.org
Cc: Gautam Dawar <gda...@xilinx.com>
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
hw/virtio/vhost-vdpa.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index
01d2101d09..5fe43a4eb5 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -275,15 +275,12 @@ static void vhost_vdpa_add_status(struct vhost_dev *dev,
uint8_t status) static int vhost_vdpa_init(struct vhost_dev *dev, void
*opaque) {
struct vhost_vdpa *v;
- uint64_t features;
assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
trace_vhost_vdpa_init(dev, opaque);
v = opaque;
v->dev = dev;
dev->opaque = opaque ;
- vhost_vdpa_call(dev, VHOST_GET_FEATURES, &features);
- dev->backend_features = features;
[GD>>] Should this be initialized with 0 here? I am not sure if memory
allocated for struct vhost_dev is initialized with 0.
v->listener = vhost_vdpa_memory_listener;
v->msg_type = VHOST_IOTLB_MSG_V2;
--
2.25.1
