From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49557) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fVBSo-000662-Es for qemu-devel@nongnu.org; Tue, 19 Jun 2018 03:54:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fVBSj-0006H2-HW for qemu-devel@nongnu.org; Tue, 19 Jun 2018 03:54:06 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:40554 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fVBSj-0006Ft-BM for qemu-devel@nongnu.org; Tue, 19 Jun 2018 03:54:01 -0400 Date: Tue, 19 Jun 2018 15:53:55 +0800 From: Wei Xu Message-ID: <20180619075355.GA23983@wei-ubt> References: <1528225683-11413-1-git-send-email-wexu@redhat.com> <1528225683-11413-9-git-send-email-wexu@redhat.com> <6972a450-117a-2f3c-fb44-fb985c35b8e6@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6972a450-117a-2f3c-fb44-fb985c35b8e6@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC v2 8/8] virtio: guest driver reload for vhost-net List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang Cc: qemu-devel@nongnu.org, tiwei.bie@intel.com, mst@redhat.com, jfreimann@redhat.com On Wed, Jun 06, 2018 at 11:48:19AM +0800, Jason Wang wrote: >=20 >=20 > On 2018=E5=B9=B406=E6=9C=8806=E6=97=A5 03:08, wexu@redhat.com wrote: > >From: Wei Xu > > > >last_avail, avail_wrap_count, used_idx and used_wrap_count are > >needed to support vhost-net backend, all these are either 16 or > >bool variables, since state.num is 64bit wide, so here it is > >possible to put them to the 'num' without introducing a new case > >while handling ioctl. > > > >Unload/Reload test has been done successfully with a patch in vhost ke= rnel. >=20 > You need a patch to enable vhost. >=20 > And I think you can only do it for vhost-kenrel now since vhost-user > protocol needs some extension I believe. OK. >=20 > > > >Signed-off-by: Wei Xu > >--- > > hw/virtio/virtio.c | 42 ++++++++++++++++++++++++++++++++++-------- > > 1 file changed, 34 insertions(+), 8 deletions(-) > > > >diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > >index 4543974..153f6d7 100644 > >--- a/hw/virtio/virtio.c > >+++ b/hw/virtio/virtio.c > >@@ -2862,33 +2862,59 @@ hwaddr virtio_queue_get_used_size(VirtIODevice= *vdev, int n) > > } > > } > >-uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n) > >+uint64_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n) > > { > >- return vdev->vq[n].last_avail_idx; > >+ uint64_t num; > >+ > >+ num =3D vdev->vq[n].last_avail_idx; > >+ if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { > >+ num |=3D ((uint64_t)vdev->vq[n].avail_wrap_counter) << 16; > >+ num |=3D ((uint64_t)vdev->vq[n].used_idx) << 32; > >+ num |=3D ((uint64_t)vdev->vq[n].used_wrap_counter) << 48; >=20 > So s.num is 32bit, I don't think this can even work. I mistakenly checked out s.num is 64bit, will add a new case in next vers= ion. Wei >=20 > Thanks >=20 > >+ } > >+ > >+ return num; > > } > >-void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint1= 6_t idx) > >+void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint6= 4_t num) > > { > >- vdev->vq[n].last_avail_idx =3D idx; > >- vdev->vq[n].shadow_avail_idx =3D idx; > >+ vdev->vq[n].shadow_avail_idx =3D vdev->vq[n].last_avail_idx =3D (= uint16_t)(num); > >+ > >+ if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { > >+ vdev->vq[n].avail_wrap_counter =3D (uint16_t)(num >> 16); > >+ vdev->vq[n].used_idx =3D (uint16_t)(num >> 32); > >+ vdev->vq[n].used_wrap_counter =3D (uint16_t)(num >> 48); > >+ } > > } > > void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n) > > { > > rcu_read_lock(); > >- if (vdev->vq[n].vring.desc) { > >+ if (!vdev->vq[n].vring.desc) { > >+ goto out; > >+ } > >+ > >+ if (!virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { > > vdev->vq[n].last_avail_idx =3D vring_used_idx(&vdev->vq[n]); > >- vdev->vq[n].shadow_avail_idx =3D vdev->vq[n].last_avail_idx; > > } > >+ vdev->vq[n].shadow_avail_idx =3D vdev->vq[n].last_avail_idx; > >+ > >+out: > > rcu_read_unlock(); > > } > > void virtio_queue_update_used_idx(VirtIODevice *vdev, int n) > > { > > rcu_read_lock(); > >- if (vdev->vq[n].vring.desc) { > >+ if (!vdev->vq[n].vring.desc) { > >+ goto out; > >+ } > >+ > >+ if (!virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { > > vdev->vq[n].used_idx =3D vring_used_idx(&vdev->vq[n]); > > } > >+ > >+out: > > rcu_read_unlock(); > > } >=20