From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Xu Subject: Re: [RFC V4 PATCH 7/8] vhost: packed ring support Date: Wed, 23 May 2018 15:17:27 +0800 Message-ID: <20180523071727.GA13373@wei-ubt> References: <1526473941-16199-1-git-send-email-jasowang@redhat.com> <1526473941-16199-8-git-send-email-jasowang@redhat.com> <20180522165448.GA13523@wei-ubt> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jfreimann@redhat.com, tiwei.bie@intel.com To: Jason Wang Return-path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:49164 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753985AbeEWHRi (ORCPT ); Wed, 23 May 2018 03:17:38 -0400 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Wed, May 23, 2018 at 09:39:28AM +0800, Jason Wang wrote: > > > On 2018年05月23日 00:54, Wei Xu wrote: > >On Wed, May 16, 2018 at 08:32:20PM +0800, Jason Wang wrote: > >>Signed-off-by: Jason Wang > >>--- > >> drivers/vhost/net.c | 3 +- > >> drivers/vhost/vhost.c | 539 ++++++++++++++++++++++++++++++++++++++++++++++---- > >> drivers/vhost/vhost.h | 8 +- > >> 3 files changed, 513 insertions(+), 37 deletions(-) > >> > >>diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > >>index 8304c30..f2a0f5b 100644 > >>--- a/drivers/vhost/vhost.c > >>+++ b/drivers/vhost/vhost.c > >>@@ -1358,6 +1382,8 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg > >> break; > >> } > >> vq->last_avail_idx = s.num; > >>+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > >>+ vq->avail_wrap_counter = s.num >> 31; > >> /* Forget the cached index value. */ > >> vq->avail_idx = vq->last_avail_idx; > >> break; > >>@@ -1366,6 +1392,8 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg > >> s.num = vq->last_avail_idx; > >> if (copy_to_user(argp, &s, sizeof s)) > >> r = -EFAULT; > >>+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > >>+ s.num |= vq->avail_wrap_counter << 31; > >> break; > >> case VHOST_SET_VRING_ADDR: > >> if (copy_from_user(&a, argp, sizeof a)) { > >'last_used_idx' also needs to be saved/restored here. > > > >I have figured out the root cause of broken device after reloading > >'virtio-net' module, all indices have been reset for a reloading but > >'last_used_idx' is not properly reset in this case. This confuses > >handle_rx()/tx(). > > > >Wei > > > > Good catch, so we probably need a new ioctl to sync between qemu and vhost. > > Something like VHOST_SET/GET_USED_BASE. Sure, or can we expand 'vhost_vring_state' to keep them done in a bunch? > > Thanks >