On Mon, Jul 16, 2018 at 11:28:09AM +0800, Jason Wang wrote: [...]> @@ -1367,10 +1397,48 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg > vq->last_avail_idx = s.num; > /* Forget the cached index value. */ > vq->avail_idx = vq->last_avail_idx; > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) { > + vq->last_avail_wrap_counter = wrap_counter; > + vq->avail_wrap_counter = vq->last_avail_wrap_counter; > + } > break; > case VHOST_GET_VRING_BASE: > s.index = idx; > s.num = vq->last_avail_idx; > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > + s.num |= vq->last_avail_wrap_counter << 31; > + if (copy_to_user(argp, &s, sizeof(s))) > + r = -EFAULT; > + break; > + case VHOST_SET_VRING_USED_BASE: > + /* Moving base with an active backend? > + * You don't want to do that. > + */ > + if (vq->private_data) { > + r = -EBUSY; > + break; > + } > + if (copy_from_user(&s, argp, sizeof(s))) { > + r = -EFAULT; > + break; > + } > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) { > + wrap_counter = s.num >> 31; > + s.num &= ~(1 << 31); > + } > + if (s.num > 0xffff) { > + r = -EINVAL; > + break; > + }Do we want to put wrap_counter at bit 15? If put wrap_counter at bit 31, the check (s.num > 0xffff) won't be able to catch the illegal index 0x8000~0xffff for packed ring.> + vq->last_used_idx = s.num; > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > + vq->last_used_wrap_counter = wrap_counter; > + break; > + case VHOST_GET_VRING_USED_BASE:Do we need the new VHOST_GET_VRING_USED_BASE and VHOST_SET_VRING_USED_BASE ops? We are going to merge below series in DPDK: http://patches.dpdk.org/patch/45874/ We may need to reach an agreement first.> + s.index = idx; > + s.num = vq->last_used_idx; > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > + s.num |= vq->last_used_wrap_counter << 31; > if (copy_to_user(argp, &s, sizeof s)) > r = -EFAULT; > break;[...]
Michael S. Tsirkin
2018-Oct-12 17:23 UTC
[PATCH net-next V2 6/8] vhost: packed ring support
On Fri, Oct 12, 2018 at 10:32:44PM +0800, Tiwei Bie wrote:> On Mon, Jul 16, 2018 at 11:28:09AM +0800, Jason Wang wrote: > [...] > > @@ -1367,10 +1397,48 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg > > vq->last_avail_idx = s.num; > > /* Forget the cached index value. */ > > vq->avail_idx = vq->last_avail_idx; > > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) { > > + vq->last_avail_wrap_counter = wrap_counter; > > + vq->avail_wrap_counter = vq->last_avail_wrap_counter; > > + } > > break; > > case VHOST_GET_VRING_BASE: > > s.index = idx; > > s.num = vq->last_avail_idx; > > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > > + s.num |= vq->last_avail_wrap_counter << 31; > > + if (copy_to_user(argp, &s, sizeof(s))) > > + r = -EFAULT; > > + break; > > + case VHOST_SET_VRING_USED_BASE: > > + /* Moving base with an active backend? > > + * You don't want to do that. > > + */ > > + if (vq->private_data) { > > + r = -EBUSY; > > + break; > > + } > > + if (copy_from_user(&s, argp, sizeof(s))) { > > + r = -EFAULT; > > + break; > > + } > > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) { > > + wrap_counter = s.num >> 31; > > + s.num &= ~(1 << 31); > > + } > > + if (s.num > 0xffff) { > > + r = -EINVAL; > > + break; > > + } > > Do we want to put wrap_counter at bit 15?I think I second that - seems to be consistent with e.g. event suppression structure and the proposed extension to driver notifications.> If put wrap_counter at bit 31, the check (s.num > 0xffff) > won't be able to catch the illegal index 0x8000~0xffff for > packed ring. > > > + vq->last_used_idx = s.num; > > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > > + vq->last_used_wrap_counter = wrap_counter; > > + break; > > + case VHOST_GET_VRING_USED_BASE: > > Do we need the new VHOST_GET_VRING_USED_BASE and > VHOST_SET_VRING_USED_BASE ops? > > We are going to merge below series in DPDK: > > http://patches.dpdk.org/patch/45874/ > > We may need to reach an agreement first. > > > > + s.index = idx; > > + s.num = vq->last_used_idx; > > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > > + s.num |= vq->last_used_wrap_counter << 31; > > if (copy_to_user(argp, &s, sizeof s)) > > r = -EFAULT; > > break; > [...]
On 2018?10?13? 01:23, Michael S. Tsirkin wrote:> On Fri, Oct 12, 2018 at 10:32:44PM +0800, Tiwei Bie wrote: >> On Mon, Jul 16, 2018 at 11:28:09AM +0800, Jason Wang wrote: >> [...] >>> @@ -1367,10 +1397,48 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg >>> vq->last_avail_idx = s.num; >>> /* Forget the cached index value. */ >>> vq->avail_idx = vq->last_avail_idx; >>> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) { >>> + vq->last_avail_wrap_counter = wrap_counter; >>> + vq->avail_wrap_counter = vq->last_avail_wrap_counter; >>> + } >>> break; >>> case VHOST_GET_VRING_BASE: >>> s.index = idx; >>> s.num = vq->last_avail_idx; >>> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) >>> + s.num |= vq->last_avail_wrap_counter << 31; >>> + if (copy_to_user(argp, &s, sizeof(s))) >>> + r = -EFAULT; >>> + break; >>> + case VHOST_SET_VRING_USED_BASE: >>> + /* Moving base with an active backend? >>> + * You don't want to do that. >>> + */ >>> + if (vq->private_data) { >>> + r = -EBUSY; >>> + break; >>> + } >>> + if (copy_from_user(&s, argp, sizeof(s))) { >>> + r = -EFAULT; >>> + break; >>> + } >>> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) { >>> + wrap_counter = s.num >> 31; >>> + s.num &= ~(1 << 31); >>> + } >>> + if (s.num > 0xffff) { >>> + r = -EINVAL; >>> + break; >>> + } >> Do we want to put wrap_counter at bit 15? > I think I second that - seems to be consistent with > e.g. event suppression structure and the proposed > extension to driver notifications.Ok, I assumes packed virtqueue support 64K but looks not. I can change it to bit 15 and GET_VRING_BASE need to be changed as well.> > >> If put wrap_counter at bit 31, the check (s.num > 0xffff) >> won't be able to catch the illegal index 0x8000~0xffff for >> packed ring. >>Do we need to clarify this in the spec?>>> + vq->last_used_idx = s.num; >>> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) >>> + vq->last_used_wrap_counter = wrap_counter; >>> + break; >>> + case VHOST_GET_VRING_USED_BASE: >> Do we need the new VHOST_GET_VRING_USED_BASE and >> VHOST_SET_VRING_USED_BASE ops? >> >> We are going to merge below series in DPDK: >> >> http://patches.dpdk.org/patch/45874/ >> >> We may need to reach an agreement first.If we agree that 64K virtqueue won't be supported, I'm ok with either. Btw the code assumes used_wrap_counter is equal to avail_wrap_counter which looks wrong? Thanks>> >>> + s.index = idx; >>> + s.num = vq->last_used_idx; >>> + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) >>> + s.num |= vq->last_used_wrap_counter << 31; >>> if (copy_to_user(argp, &s, sizeof s)) >>> r = -EFAULT; >>> break; >> [...]