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Tsirkin" , Dragos Tatulea , Shannon Nelson Subject: [RFC PATCH 00/12] Prefer to use SVQ to stall dataplane at NIC state restore through CVQ Date: Thu, 20 Jul 2023 20:14:47 +0200 Message-Id: <20230720181459.607008-1-eperezma@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=eperezma@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org At this moment the migration of net features that depends on CVQ is not=0D possible, as there is no reliable way to restore the device state like mac= =0D address, number of enabled queues, etc to the destination. This is mainly= =0D caused because the device must only read CVQ, and process all the commands= =0D before resuming the dataplane.=0D =0D This series uses the VirtIO feature _F_RING_RESET to achieve it, adding an= =0D alternative method to late vq enabling proposed in [1][2]. It expose SVQ t= o=0D the device until it process all the CVQ messages, and then replaces the vri= ng=0D for the guest's one.=0D =0D As an advantage, it uses a feature well deviced in the VirtIO standard. As= a=0D disadvantage, current HW already support the late enabling and it does not= =0D support RING_RESET.=0D =0D This patch must be applied on top of the series ("Enable vdpa net migration= =0D with features depending on CVQ") [1][2].=0D =0D The patch has been tested with vp_vdpa, but using high IOVA instead of a=0D sepparated ID for shadow CVQ and shadow temporal vrings.=0D =0D [1] Message-id: <20230706191227.835526-1-eperezma@redhat.com>=0D [2] https://lists.nongnu.org/archive/html/qemu-devel/2023-07/msg01325.html= =0D =0D Eugenio P=C3=A9rez (12):=0D vhost: add vhost_reset_queue_op=0D vhost: add vhost_restart_queue_op=0D vhost_net: Use ops->vhost_restart_queue in vhost_net_virtqueue_restart=0D vhost_net: Use ops->vhost_reset_queue in vhost_net_virtqueue_reset=0D vdpa: add vhost_vdpa_set_vring_ready_internal=0D vdpa: add vhost_vdpa_svq_stop=0D vdpa: add vhost_vdpa_reset_queue=0D vdpa: add vhost_vdpa_svq_start=0D vdpa: add vhost_vdpa_restart_queue=0D vdpa: enable all vqs if the device support RING_RESET feature=0D vdpa: use SVQ to stall dataplane while NIC state is being restored=0D vhost: Allow _F_RING_RESET with shadow virtqueue=0D =0D include/hw/virtio/vhost-backend.h | 6 ++=0D hw/net/vhost_net.c | 16 ++--=0D hw/virtio/vhost-shadow-virtqueue.c | 1 +=0D hw/virtio/vhost-vdpa.c | 139 +++++++++++++++++++++--------=0D net/vhost-vdpa.c | 55 ++++++++++--=0D hw/virtio/trace-events | 2 +-=0D 6 files changed, 171 insertions(+), 48 deletions(-)=0D =0D -- =0D 2.39.3=0D =0D