From: Jason Wang <jasowang@redhat.com> To: "Eugenio Pérez" <eperezma@redhat.com>, qemu-devel@nongnu.org Cc: Parav Pandit <parav@mellanox.com>, "Michael S. Tsirkin" <mst@redhat.com>, Guru Prasad <guru.prasad@broadcom.com>, Juan Quintela <quintela@redhat.com>, Markus Armbruster <armbru@redhat.com>, virtualization@lists.linux-foundation.org, Harpreet Singh Anand <hanand@xilinx.com>, Xiao W Wang <xiao.w.wang@intel.com>, Eli Cohen <eli@mellanox.com>, Stefano Garzarella <sgarzare@redhat.com>, Michael Lilja <ml@napatech.com>, Jim Harford <jim.harford@broadcom.com>, Rob Miller <rob.miller@broadcom.com> Subject: Re: [RFC v2 10/13] vhost: add vhost_kernel_set_vring_enable Date: Tue, 16 Mar 2021 15:29:45 +0800 [thread overview] Message-ID: <98916095-ac78-7deb-5086-ee0adf39dcf5@redhat.com> (raw) In-Reply-To: <20210315194842.277740-11-eperezma@redhat.com> 在 2021/3/16 上午3:48, Eugenio Pérez 写道: > This method is already present in vhost-user. This commit adapts it to > vhost-net, so SVQ can use. > > vhost_kernel_set_enable stops the device, so qemu can ask for its status > (next available idx the device was going to consume). When SVQ starts it > can resume consuming the guest's driver ring, without notice from the > latter. Not stopping the device before of the swapping could imply that > it process more buffers than reported, what would duplicate the device > action. Note that it might not be the case of vDPA (virtio) or at least virtio needs some extension to achieve something similar like this. One example is virtio-pci which forbids 0 to be wrote to queue_enable. This is another reason to start from vhost-vDPA. > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com> > --- > hw/virtio/vhost-backend.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c > index 31b33bde37..1ac5c574a9 100644 > --- a/hw/virtio/vhost-backend.c > +++ b/hw/virtio/vhost-backend.c > @@ -201,6 +201,34 @@ static int vhost_kernel_get_vq_index(struct vhost_dev *dev, int idx) > return idx - dev->vq_index; > } > > +static int vhost_kernel_set_vq_enable(struct vhost_dev *dev, unsigned idx, > + bool enable) > +{ > + struct vhost_vring_file file = { > + .index = idx, > + }; > + > + if (!enable) { > + file.fd = -1; /* Pass -1 to unbind from file. */ > + } else { > + struct vhost_net *vn_dev = container_of(dev, struct vhost_net, dev); > + file.fd = vn_dev->backend; This can only work with vhost-net devices but not vsock/scsi etc. Thanks > + } > + > + return vhost_kernel_net_set_backend(dev, &file); > +} > + > +static int vhost_kernel_set_vring_enable(struct vhost_dev *dev, int enable) > +{ > + int i; > + > + for (i = 0; i < dev->nvqs; ++i) { > + vhost_kernel_set_vq_enable(dev, i, enable); > + } > + > + return 0; > +} > + > #ifdef CONFIG_VHOST_VSOCK > static int vhost_kernel_vsock_set_guest_cid(struct vhost_dev *dev, > uint64_t guest_cid) > @@ -317,6 +345,7 @@ static const VhostOps kernel_ops = { > .vhost_set_owner = vhost_kernel_set_owner, > .vhost_reset_device = vhost_kernel_reset_device, > .vhost_get_vq_index = vhost_kernel_get_vq_index, > + .vhost_set_vring_enable = vhost_kernel_set_vring_enable, > #ifdef CONFIG_VHOST_VSOCK > .vhost_vsock_set_guest_cid = vhost_kernel_vsock_set_guest_cid, > .vhost_vsock_set_running = vhost_kernel_vsock_set_running,
WARNING: multiple messages have this Message-ID (diff)
From: Jason Wang <jasowang@redhat.com> To: "Eugenio Pérez" <eperezma@redhat.com>, qemu-devel@nongnu.org Cc: Parav Pandit <parav@mellanox.com>, "Michael S. Tsirkin" <mst@redhat.com>, Guru Prasad <guru.prasad@broadcom.com>, virtualization@lists.linux-foundation.org, Harpreet Singh Anand <hanand@xilinx.com>, Xiao W Wang <xiao.w.wang@intel.com>, Eli Cohen <eli@mellanox.com>, Eric Blake <eblake@redhat.com>, Michael Lilja <ml@napatech.com>, Jim Harford <jim.harford@broadcom.com>, Rob Miller <rob.miller@broadcom.com> Subject: Re: [RFC v2 10/13] vhost: add vhost_kernel_set_vring_enable Date: Tue, 16 Mar 2021 15:29:45 +0800 [thread overview] Message-ID: <98916095-ac78-7deb-5086-ee0adf39dcf5@redhat.com> (raw) In-Reply-To: <20210315194842.277740-11-eperezma@redhat.com> 在 2021/3/16 上午3:48, Eugenio Pérez 写道: > This method is already present in vhost-user. This commit adapts it to > vhost-net, so SVQ can use. > > vhost_kernel_set_enable stops the device, so qemu can ask for its status > (next available idx the device was going to consume). When SVQ starts it > can resume consuming the guest's driver ring, without notice from the > latter. Not stopping the device before of the swapping could imply that > it process more buffers than reported, what would duplicate the device > action. Note that it might not be the case of vDPA (virtio) or at least virtio needs some extension to achieve something similar like this. One example is virtio-pci which forbids 0 to be wrote to queue_enable. This is another reason to start from vhost-vDPA. > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com> > --- > hw/virtio/vhost-backend.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c > index 31b33bde37..1ac5c574a9 100644 > --- a/hw/virtio/vhost-backend.c > +++ b/hw/virtio/vhost-backend.c > @@ -201,6 +201,34 @@ static int vhost_kernel_get_vq_index(struct vhost_dev *dev, int idx) > return idx - dev->vq_index; > } > > +static int vhost_kernel_set_vq_enable(struct vhost_dev *dev, unsigned idx, > + bool enable) > +{ > + struct vhost_vring_file file = { > + .index = idx, > + }; > + > + if (!enable) { > + file.fd = -1; /* Pass -1 to unbind from file. */ > + } else { > + struct vhost_net *vn_dev = container_of(dev, struct vhost_net, dev); > + file.fd = vn_dev->backend; This can only work with vhost-net devices but not vsock/scsi etc. Thanks > + } > + > + return vhost_kernel_net_set_backend(dev, &file); > +} > + > +static int vhost_kernel_set_vring_enable(struct vhost_dev *dev, int enable) > +{ > + int i; > + > + for (i = 0; i < dev->nvqs; ++i) { > + vhost_kernel_set_vq_enable(dev, i, enable); > + } > + > + return 0; > +} > + > #ifdef CONFIG_VHOST_VSOCK > static int vhost_kernel_vsock_set_guest_cid(struct vhost_dev *dev, > uint64_t guest_cid) > @@ -317,6 +345,7 @@ static const VhostOps kernel_ops = { > .vhost_set_owner = vhost_kernel_set_owner, > .vhost_reset_device = vhost_kernel_reset_device, > .vhost_get_vq_index = vhost_kernel_get_vq_index, > + .vhost_set_vring_enable = vhost_kernel_set_vring_enable, > #ifdef CONFIG_VHOST_VSOCK > .vhost_vsock_set_guest_cid = vhost_kernel_vsock_set_guest_cid, > .vhost_vsock_set_running = vhost_kernel_vsock_set_running, _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-03-16 7:31 UTC|newest] Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-15 19:48 [RFC v2 00/13] vDPA software assisted live migration Eugenio Pérez 2021-03-15 19:48 ` [RFC v2 01/13] virtio: Add virtio_queue_is_host_notifier_enabled Eugenio Pérez 2021-03-15 19:48 ` [RFC v2 02/13] vhost: Save masked_notifier state Eugenio Pérez 2021-03-15 19:48 ` [RFC v2 03/13] vhost: Add VhostShadowVirtqueue Eugenio Pérez 2021-03-15 19:48 ` [RFC v2 04/13] vhost: Add x-vhost-enable-shadow-vq qmp Eugenio Pérez 2021-03-16 13:37 ` Eric Blake 2021-03-16 13:37 ` Eric Blake 2021-03-15 19:48 ` [RFC v2 05/13] vhost: Route guest->host notification through shadow virtqueue Eugenio Pérez 2021-03-16 7:18 ` Jason Wang 2021-03-16 7:18 ` Jason Wang 2021-03-16 10:31 ` Eugenio Perez Martin 2021-03-17 2:05 ` Jason Wang 2021-03-17 2:05 ` Jason Wang 2021-03-17 16:47 ` Eugenio Perez Martin 2021-03-18 3:10 ` Jason Wang 2021-03-18 3:10 ` Jason Wang 2021-03-18 9:18 ` Eugenio Perez Martin 2021-03-18 9:29 ` Jason Wang 2021-03-18 9:29 ` Jason Wang 2021-03-18 10:48 ` Eugenio Perez Martin 2021-03-18 12:04 ` Eugenio Perez Martin 2021-03-19 6:55 ` Jason Wang 2021-03-19 6:55 ` Jason Wang 2021-03-15 19:48 ` [RFC v2 06/13] vhost: Route host->guest " Eugenio Pérez 2021-03-16 7:21 ` Jason Wang 2021-03-15 19:48 ` [RFC v2 07/13] vhost: Avoid re-set masked notifier in shadow vq Eugenio Pérez 2021-03-15 19:48 ` [RFC v2 08/13] virtio: Add vhost_shadow_vq_get_vring_addr Eugenio Pérez 2021-03-16 7:50 ` Jason Wang 2021-03-16 7:50 ` Jason Wang 2021-03-16 15:20 ` Eugenio Perez Martin 2021-05-17 17:39 ` Eugenio Perez Martin 2021-03-15 19:48 ` [RFC v2 09/13] virtio: Add virtio_queue_full Eugenio Pérez 2021-03-15 19:48 ` [RFC v2 10/13] vhost: add vhost_kernel_set_vring_enable Eugenio Pérez 2021-03-16 7:29 ` Jason Wang [this message] 2021-03-16 7:29 ` Jason Wang 2021-03-16 10:43 ` Eugenio Perez Martin 2021-03-17 2:25 ` Jason Wang 2021-03-17 2:25 ` Jason Wang 2021-03-15 19:48 ` [RFC v2 11/13] vhost: Shadow virtqueue buffers forwarding Eugenio Pérez 2021-03-16 8:15 ` Jason Wang 2021-03-16 8:15 ` Jason Wang 2021-03-16 16:05 ` Eugenio Perez Martin 2021-03-17 2:50 ` Jason Wang 2021-03-17 2:50 ` Jason Wang 2021-03-17 14:38 ` Eugenio Perez Martin 2021-03-18 3:14 ` Jason Wang 2021-03-18 3:14 ` Jason Wang 2021-03-18 8:06 ` Eugenio Perez Martin 2021-03-18 9:16 ` Jason Wang 2021-03-18 9:54 ` Eugenio Perez Martin 2021-03-15 19:48 ` [RFC v2 12/13] vhost: Check for device VRING_USED_F_NO_NOTIFY at shadow virtqueue kick Eugenio Pérez 2021-03-16 8:07 ` Jason Wang 2021-03-16 8:07 ` Jason Wang 2021-05-17 17:11 ` Eugenio Perez Martin 2021-03-15 19:48 ` [RFC v2 13/13] vhost: Use VRING_AVAIL_F_NO_INTERRUPT at device call on shadow virtqueue Eugenio Pérez 2021-03-16 8:08 ` Jason Wang 2021-03-16 8:08 ` Jason Wang 2021-05-17 17:32 ` Eugenio Perez Martin 2021-03-16 8:28 ` [RFC v2 00/13] vDPA software assisted live migration Jason Wang 2021-03-16 8:28 ` Jason Wang 2021-03-16 17:25 ` Eugenio Perez Martin
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