Messages in this thread |  | | Subject | Re: [PATCH] vhost: introduce mdev based hardware backend | From | Jason Wang <> | Date | Fri, 27 Sep 2019 11:27:12 +0800 |
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On 2019/9/26 下午9:14, Tiwei Bie wrote: > On Thu, Sep 26, 2019 at 04:35:18AM -0400, Michael S. Tsirkin wrote: >> On Thu, Sep 26, 2019 at 12:54:27PM +0800, Tiwei Bie wrote: > [...] >>> diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h >>> index 40d028eed645..5afbc2f08fa3 100644 >>> --- a/include/uapi/linux/vhost.h >>> +++ b/include/uapi/linux/vhost.h >>> @@ -116,4 +116,12 @@ >>> #define VHOST_VSOCK_SET_GUEST_CID _IOW(VHOST_VIRTIO, 0x60, __u64) >>> #define VHOST_VSOCK_SET_RUNNING _IOW(VHOST_VIRTIO, 0x61, int) >>> >>> +/* VHOST_MDEV specific defines */ >>> + >>> +#define VHOST_MDEV_SET_STATE _IOW(VHOST_VIRTIO, 0x70, __u64) >>> + >>> +#define VHOST_MDEV_S_STOPPED 0 >>> +#define VHOST_MDEV_S_RUNNING 1 >>> +#define VHOST_MDEV_S_MAX 2 >>> + >>> #endif >> So assuming we have an underlying device that behaves like virtio: > I think they are really good questions/suggestions. Thanks! > >> 1. Should we use SET_STATUS maybe? > I like this idea. I will give it a try. > >> 2. Do we want a reset ioctl? > I think it is helpful. If we use SET_STATUS, maybe we > can use it to support the reset. > >> 3. Do we want ability to enable rings individually? > I will make it possible at least in the vhost layer.
Note the API support e.g set_vq_ready().
> >> 4. Does device need to limit max ring size? >> 5. Does device need to limit max number of queues? > I think so. It's helpful to have ioctls to report the max > ring size and max number of queues.
An issue is the max number of queues is done through a device specific way, usually device configuration space. This is supported by the transport API, but how to expose it to userspace may need more thought.
Thanks
> > Thanks!
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