Jason Wang
2022-Jan-18 03:06 UTC
[RFC 1/3] vdpa: support exposing the config size to userspace
? 2022/1/17 ??5:29, Longpeng(Mike) ??:> From: Longpeng <longpeng2 at huawei.com> > > - GET_CONFIG_SIZE: the size of the virtio config spaceI think we need to be verbose here. And it would be better to quote what spec said: " The device MUST allow reading of any device-specific configuration field before FEATURES_OK is set by the driver. This includes fields which are conditional on feature bits, as long as those feature bits are offered by the device. " I guess the size should contain the conditional on features bits. (Or maybe we need to tweak the comment for get_config_size as well). Other looks good. Thanks> > Signed-off-by: Longpeng <longpeng2 at huawei.com> > --- > drivers/vhost/vdpa.c | 17 +++++++++++++++++ > include/uapi/linux/vhost.h | 4 ++++ > 2 files changed, 21 insertions(+) > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index 29cced1cd277..1eea14a4ea56 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -355,6 +355,20 @@ static long vhost_vdpa_get_iova_range(struct vhost_vdpa *v, u32 __user *argp) > return 0; > } > > +static long vhost_vdpa_get_config_size(struct vhost_vdpa *v, u32 __user *argp) > +{ > + struct vdpa_device *vdpa = v->vdpa; > + const struct vdpa_config_ops *ops = vdpa->config; > + u32 size; > + > + size = ops->get_config_size(vdpa); > + > + if (copy_to_user(argp, &size, sizeof(size))) > + return -EFAULT; > + > + return 0; > +} > + > static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, > void __user *argp) > { > @@ -492,6 +506,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, > case VHOST_VDPA_GET_IOVA_RANGE: > r = vhost_vdpa_get_iova_range(v, argp); > break; > + case VHOST_VDPA_GET_CONFIG_SIZE: > + r = vhost_vdpa_get_config_size(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 c998860d7bbc..bc74e95a273a 100644 > --- a/include/uapi/linux/vhost.h > +++ b/include/uapi/linux/vhost.h > @@ -150,4 +150,8 @@ > /* Get the valid iova range */ > #define VHOST_VDPA_GET_IOVA_RANGE _IOR(VHOST_VIRTIO, 0x78, \ > struct vhost_vdpa_iova_range) > + > +/* Get the config size */ > +#define VHOST_VDPA_GET_CONFIG_SIZE _IOR(VHOST_VIRTIO, 0x79, __u32) > + > #endif