lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 1 Sep 2022 13:54:28 +0800 From: Guo Zhi <qtxuning1999@...u.edu.cn> To: eperezma@...hat.com, jasowang@...hat.com, sgarzare@...hat.com, mst@...hat.com Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org, kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org, Guo Zhi <qtxuning1999@...u.edu.cn> Subject: [RFC v3 1/7] vhost: expose used buffers Follow VIRTIO 1.1 spec, only writing out a single used ring for a batch of descriptors. Signed-off-by: Guo Zhi <qtxuning1999@...u.edu.cn> --- drivers/vhost/vhost.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 40097826cff0..26862c8bf751 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2376,10 +2376,20 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq, vring_used_elem_t __user *used; u16 old, new; int start; + int copy_n = count; + /** + * If in order feature negotiated, devices can notify the use of a batch of buffers to + * the driver by only writing out a single used ring entry with the id corresponding + * to the head entry of the descriptor chain describing the last buffer in the batch. + */ + if (vhost_has_feature(vq, VIRTIO_F_IN_ORDER)) { + copy_n = 1; + heads = &heads[count - 1]; + } start = vq->last_used_idx & (vq->num - 1); used = vq->used->ring + start; - if (vhost_put_used(vq, heads, start, count)) { + if (vhost_put_used(vq, heads, start, copy_n)) { vq_err(vq, "Failed to write used"); return -EFAULT; } @@ -2388,7 +2398,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq, smp_wmb(); /* Log used ring entry write. */ log_used(vq, ((void __user *)used - (void __user *)vq->used), - count * sizeof *used); + copy_n * sizeof(*used)); } old = vq->last_used_idx; new = (vq->last_used_idx += count); @@ -2410,7 +2420,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, start = vq->last_used_idx & (vq->num - 1); n = vq->num - start; - if (n < count) { + if (n < count && !vhost_has_feature(vq, VIRTIO_F_IN_ORDER)) { r = __vhost_add_used_n(vq, heads, n); if (r < 0) return r; -- 2.17.1
Powered by blists - more mailing lists