From 8801ccd0500437a86e3d15a806f37ebb84605dce Mon Sep 17 00:00:00 2001 From: Si-Wei Liu Date: Sat, 8 Oct 2022 00:58:58 -0700 Subject: [PATCH] vhost-vdpa: allow passing opened vhostfd to vhost-vdpa MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Similar to other vhost backends, vhostfd can be passed to vhost-vdpa backend as another parameter to instantiate vhost-vdpa net client. This would benefit the use case where only open file descriptors, as opposed to raw vhost-vdpa device paths, are accessible from the QEMU process. (qemu) netdev_add type=vhost-vdpa,vhostfd=61,id=vhost-vdpa1 Signed-off-by: Si-Wei Liu Acked-by: Eugenio Pérez Signed-off-by: Jason Wang --- net/vhost-vdpa.c | 25 ++++++++++++++++++++----- qapi/net.json | 3 +++ qemu-options.hx | 6 ++++-- 3 files changed, 27 insertions(+), 7 deletions(-) diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c index 6d64000202..9c1b25d782 100644 --- a/net/vhost-vdpa.c +++ b/net/vhost-vdpa.c @@ -634,14 +634,29 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name, assert(netdev->type == NET_CLIENT_DRIVER_VHOST_VDPA); opts = &netdev->u.vhost_vdpa; - if (!opts->vhostdev) { - error_setg(errp, "vdpa character device not specified with vhostdev"); + if (!opts->has_vhostdev && !opts->has_vhostfd) { + error_setg(errp, + "vhost-vdpa: neither vhostdev= nor vhostfd= was specified"); return -1; } - vdpa_device_fd = qemu_open(opts->vhostdev, O_RDWR, errp); - if (vdpa_device_fd == -1) { - return -errno; + if (opts->has_vhostdev && opts->has_vhostfd) { + error_setg(errp, + "vhost-vdpa: vhostdev= and vhostfd= are mutually exclusive"); + return -1; + } + + if (opts->has_vhostdev) { + vdpa_device_fd = qemu_open(opts->vhostdev, O_RDWR, errp); + if (vdpa_device_fd == -1) { + return -errno; + } + } else if (opts->has_vhostfd) { + vdpa_device_fd = monitor_fd_param(monitor_cur(), opts->vhostfd, errp); + if (vdpa_device_fd == -1) { + error_prepend(errp, "vhost-vdpa: unable to parse vhostfd: "); + return -1; + } } r = vhost_vdpa_get_features(vdpa_device_fd, &features, errp); diff --git a/qapi/net.json b/qapi/net.json index dd088c09c5..926ecc8cca 100644 --- a/qapi/net.json +++ b/qapi/net.json @@ -442,6 +442,8 @@ # @vhostdev: path of vhost-vdpa device # (default:'/dev/vhost-vdpa-0') # +# @vhostfd: file descriptor of an already opened vhost vdpa device +# # @queues: number of queues to be created for multiqueue vhost-vdpa # (default: 1) # @@ -456,6 +458,7 @@ { 'struct': 'NetdevVhostVDPAOptions', 'data': { '*vhostdev': 'str', + '*vhostfd': 'str', '*queues': 'int', '*x-svq': {'type': 'bool', 'features' : [ 'unstable'] } } } diff --git a/qemu-options.hx b/qemu-options.hx index eb38e5dc40..876a70aa63 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -2790,8 +2790,10 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, " configure a vhost-user network, backed by a chardev 'dev'\n" #endif #ifdef __linux__ - "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" + "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" + " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" + " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" #endif #ifdef CONFIG_VMNET "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" @@ -3296,7 +3298,7 @@ SRST -netdev type=vhost-user,id=net0,chardev=chr0 \ -device virtio-net-pci,netdev=net0 -``-netdev vhost-vdpa,vhostdev=/path/to/dev`` +``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` Establish a vhost-vdpa netdev. vDPA device is a device that uses a datapath which complies with