RE: [RFC 2/3] vdpa: support exposing the count of vqs to userspace

Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2022-03-10T03:16:17Z

Hi Jason,

> -----Original Message-----
> From: Jason Wang [mailto:jasowang@redhat.com]
> Sent: Tuesday, January 18, 2022 11:08 AM
> To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> <longpeng2@huawei.com>; mst@redhat.com; sgarzare@redhat.com;
> stefanha@redhat.com
> Cc: virtualization@lists.linux-foundation.org; kvm@vger.kernel.org;
> linux-kernel@vger.kernel.org; netdev@vger.kernel.org; Gonglei (Arei)
> <arei.gonglei@huawei.com>; Yechuan <yechuan@huawei.com>; Huangzhichao
> <huangzhichao@huawei.com>
> Subject: Re: [RFC 2/3] vdpa: support exposing the count of vqs to userspace
>
>
> 在 2022/1/17 下午5:29, Longpeng(Mike) 写道:
> > From: Longpeng <longpeng2@huawei.com>
> >
> > - GET_VQS_COUNT: the count of virtqueues that exposed
> >
> > Signed-off-by: Longpeng <longpeng2@huawei.com>
> > ---
> > drivers/vhost/vdpa.c | 13 +++++++++++++
> > include/uapi/linux/vhost.h | 3 +++
> > 2 files changed, 16 insertions(+)
> >
> > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> > index 1eea14a4ea56..c1074278fc6b 100644
> > --- a/drivers/vhost/vdpa.c
> > +++ b/drivers/vhost/vdpa.c
> > @@ -369,6 +369,16 @@ static long vhost_vdpa_get_config_size(struct vhost_vdpa
> *v, u32 __user *argp)
> > return 0;
> > }
> >
> > +static long vhost_vdpa_get_vqs_count(struct vhost_vdpa *v, u32 __user *argp)
> > +{
> > + struct vdpa_device *vdpa = v->vdpa;
>
>
> While at it, I think it's better to change vdpa->nvqs to use u32?
>

struct vhost_vdpa {
...
int nvqs;
...
};

struct vdpa_device {
...
int nvqs;
...
};

I think we should change both to u32?

> Thanks
>
>
> > +
> > + if (copy_to_user(argp, &vdpa->nvqs, sizeof(vdpa->nvqs)))
> > + return -EFAULT;
> > +
> > + return 0;
> > +}
> > +
> > static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
> > void __user *argp)
> > {
> > @@ -509,6 +519,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
> > case VHOST_VDPA_GET_CONFIG_SIZE:
> > r = vhost_vdpa_get_config_size(v, argp);
> > break;
> > + case VHOST_VDPA_GET_VQS_COUNT:
> > + r = vhost_vdpa_get_vqs_count(v, argp);
> > + break;
> > default:
> > r = vhost_dev_ioctl(&v->vdev, cmd, argp);
> > if (r == -ENOIOCTLCMD)
> > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
> > index bc74e95a273a..5d99e7c242a2 100644
> > --- a/include/uapi/linux/vhost.h
> > +++ b/include/uapi/linux/vhost.h
> > @@ -154,4 +154,7 @@
> > /* Get the config size */
> > #define VHOST_VDPA_GET_CONFIG_SIZE _IOR(VHOST_VIRTIO, 0x79, __u32)
> >
> > +/* Get the count of all virtqueues */
> > +#define VHOST_VDPA_GET_VQS_COUNT _IOR(VHOST_VIRTIO, 0x80, __u32)
> > +
> > #endif