On 2020/9/24 上午3:12, Mike Christie wrote:
On 9/21/20 9:02 PM, Jason Wang wrote:
On 2020/9/22 上午2:23, Mike Christie wrote:
This adds a helper check if a vq has been setup. The next patches
will use this when we move the vhost scsi cmd preallocation from per
session to per vq. In the per vq case, we only want to allocate cmds
for vqs that have actually been setup and not for all the possible
vqs.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 9 +++++++++
drivers/vhost/vhost.h | 1 +
2 files changed, 10 insertions(+)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b45519c..5dd9eb1 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -305,6 +305,15 @@ static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)
spin_lock_init(&call_ctx->ctx_lock);
}
+bool vhost_vq_is_setup(struct vhost_virtqueue *vq)
+{
+ if (vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq))
+ return true;
+ else
+ return false;
+}
+EXPORT_SYMBOL_GPL(vhost_vq_is_setup);
This is probably ok but I wonder maybe we should have something like what vDPA did (VHOST_SET_VRING_ENABLE) to match virtio 1.0 device definition.
It looks like I can make that work. Some questions:
1. Do you mean a generic VHOST_SET_VRING_ENABLE or a SCSI specific one VHOST_SCSI_SET_VRING_ENABLE?
It would be better if we can make it generic.
2. I can see the VHOST_VDPA_SET_VRING_ENABLE kernel code and the vhost_set_vring_enable qemu code, so I have an idea of how it should work for vhost scsi. However, I'm not sure the requirements for a generic VHOST_SET_VRING_ENABLE if that is what you meant. I could not find it in the spec either. Could you send me a pointer to the section?
In the spec, for PCI, it's the queue_enable for modern device.
For example, for vhost-net we seem to enable a device in the VHOST_NET_SET_BACKEND ioctl, so I'm not sure what behavior should be or needs to be implemented for net and vsock.
Yes, but VHOST_NET_SET_BACKEND is for the whole device not a specific
virtqueue.
Thanks
