From: Jason Wang <jasowang@redhat.com>
To: Tiwei Bie <tiwei.bie@intel.com>, "Michael S. Tsirkin" <mst@redhat.com>
Cc: alex.williamson@redhat.com, maxime.coquelin@redhat.com,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, dan.daly@intel.com,
cunming.liang@intel.com, zhihong.wang@intel.com,
lingshan.zhu@intel.com
Subject: Re: [PATCH] vhost: introduce mdev based hardware backend
Date: Fri, 27 Sep 2019 11:27:12 +0800 [thread overview]
Message-ID: <8ab5a8d9-284d-bba5-803d-08523c0814e1@redhat.com> (raw)
In-Reply-To: <20190926131439.GA11652@___>
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!
next prev parent reply other threads:[~2019-09-27 3:27 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 4:54 [PATCH] vhost: introduce mdev based hardware backend Tiwei Bie
2019-09-26 8:35 ` Michael S. Tsirkin
2019-09-26 13:14 ` Tiwei Bie
2019-09-26 13:26 ` Michael S. Tsirkin
2019-09-26 13:34 ` Tiwei Bie
2019-09-27 3:27 ` Jason Wang [this message]
2019-09-27 9:41 ` Michael S. Tsirkin
2019-09-27 12:17 ` Jason Wang
2019-09-27 12:46 ` Michael S. Tsirkin
2019-09-27 13:17 ` Jason Wang
2019-09-27 13:23 ` Michael S. Tsirkin
2019-09-29 7:39 ` Jason Wang
2019-09-26 14:05 ` kbuild test robot
2019-09-27 3:46 ` Jason Wang
2019-09-27 3:51 ` Jason Wang
2019-09-27 4:26 ` Tiwei Bie
2019-09-27 4:54 ` Tiwei Bie
2019-09-27 7:14 ` Jason Wang
2019-09-27 8:04 ` Tiwei Bie
2019-09-27 8:31 ` Jason Wang
2019-09-27 7:17 ` Jason Wang
2019-09-27 8:47 ` Jason Wang
2019-09-27 9:38 ` Michael S. Tsirkin
2019-09-27 12:15 ` Jason Wang
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