On Tue, Mar 4, 2014 at 7:29 PM, Paolo Bonzini <pbonz...@redhat.com> wrote:
> Il 04/03/2014 19:22, Antonios Motakis ha scritto: > > In this patch series we would like to introduce our approach for putting a >> virtio-net backend in an external userspace process. Our eventual target >> is to >> run the network backend in the Snabbswitch ethernet switch, while >> receiving >> traffic from a guest inside QEMU/KVM which runs an unmodified virtio-net >> implementation. >> >> For this, we are working into extending vhost to allow equivalent >> functionality >> for userspace. Vhost already passes control of the data plane of >> virtio-net to >> the host kernel; we want to realize a similar model, but for userspace. >> >> In this patch series the concept of a vhost-backend is introduced. >> >> We define two vhost backend types - vhost-kernel and vhost-user. The >> former is >> the interface to the current kernel module implementation. Its control >> plane is >> ioctl based. The data plane is realized by the kernel directly accessing >> the >> QEMU allocated, guest memory. >> >> In the new vhost-user backend, the control plane is based on communication >> between QEMU and another userspace process using a unix domain socket. >> This >> allows to implement a virtio backend for a guest running in QEMU, inside >> the >> other userspace process. For this communication we use a chardev with a >> Unix >> domain socket backend. Vhost-user is client/server agnostic regarding the >> chardev, however it does not support the 'nowait' and 'telnet' options. >> >> A reconnection in 'server' mode is supported, but the backend's exposed >> virtio >> features need to be compatible with the first connected slave. >> >> We change -mem-path to QemuOpts and add prealloc and share as properties >> to it. HugeTLBFS is required for this option to work. >> >> The data path is realized by directly accessing the vrings and the buffer >> data >> off the guest's memory. >> >> The current user of vhost-user is only vhost-net. We add new netdev >> backend >> that is intended to initialize vhost-net with vhost-user backend. >> >> Example usage: >> >> qemu -m 1024 -mem-path /hugetlbfs,share=on \ >> -chardev socket,id=chr0,path=/path/to/ >> socket \ >> -netdev type=vhost-user,id=net0,chardev=chr0 \ >> -device virtio-net-pci,netdev=net0 >> >> On non-MSIX guests the vhost feture can be forced using a special option: >> >> ... >> -netdev type=vhost-user,id=net0,chardev=chr0,vhostforce >> ... >> >> In order to use ioeventfds, kvm should be enabled. >> >> This code can be pulled from g...@github.com:virtualopensystems/qemu.git >> vhost-user-v9 >> A simple functional test is available in tests/vhost-user-test.c >> >> A reference vhost-user slave for testing is also available from >> g...@github.com:virtualopensystems/vapp.git >> > > Hi, > > did you see the series I posted today? It would be great if you tested > vhost-user on top of it. The replacement for the above -mem-path > incantation should be the following: > > -object memory-file,id=mem,path=/hugetlbfs,share=on \ > -numa node,memdev=mem > Hello Paolo, Yes we saw your series today, and we plan to try it out. Any idea on when your series will get in? Then we can probably remove our own implementation for shared memory. > > Do the ideas behind vhost-user work if you have multiple hugetlbfs files, > one per node? > > Yes, they should work. Best regards > Paolo > > > Changes from v8: >> - Removed prealloc property from the -mem-path refactoring >> - Added and use new function - kvm_eventfds_enabled >> - Add virtio_queue_get_avail_idx used in vhost_virtqueue_stop to >> get a sane value in case of VHOST_GET_VRING_BASE failure >> - vhost user uses kvm_eventfds_enabled to check whether the ioeventfd >> capability of KVM is available >> - Added flag VHOST_USER_VRING_NOFD_MASK to be set when KICK, CALL or ERR >> file >> descriptor is invalid or ioeventfd is not available >> >> Changes from v7: >> - Slave reconnection when using chardev in server mode >> - qtest vhost-user-test added >> - New qemu_chr_fe_get_msgfds for reading multiple fds from the chardev >> - Mandatory features in vhost_dev, used on reconnect to verify for >> conflicts >> - Add vhostforce parameter to -netdev vhost-user (for non-MSIX guests) >> - Extend libqemustub.a to support qemu-char.c >> >> Changes from v6: >> - Remove the 'unlink' property of '-mem-path' >> - Extend qemu-char: blocking read, send fds, monitor for connection close >> - Vhost-user uses chardev as a backend >> - Poll and reconnect removed (no VHOST_USER_ECHO). >> - Disconnect is deteced by the chardev (G_IO_HUP event) >> - vhost-backend.c split to vhost-user.c >> >> Changes from v5: >> - Split -mem-path unlink option to a separate patch >> - Fds are passed only in the ancillary data >> - Stricter message size checks on receive/send >> - Netdev vhost-user now includes path and poll_time options >> - The connection probing interval is configurable >> >> Changes from v4: >> - Use error_report for errors >> - VhostUserMsg has new field `size` indicating the following payload >> length. >> Field `flags` now has version and reply bits. The structure is packed. >> - Send data is of variable length (`size` field in message) >> - Receive in 2 steps, header and payload >> - Add new message type VHOST_USER_ECHO, to check connection status >> >> Changes from v3: >> - Convert -mem-path to QemuOpts with prealloc, share and unlink >> properties >> - Set 1 sec timeout when read/write to the unix domain socket >> - Fix file descriptor leak >> >> Changes from v2: >> - Reconnect when the backend disappears >> >> Changes from v1: >> - Implementation of vhost-user netdev backend >> - Code improvements >> >> Antonios Motakis (20): >> Convert -mem-path to QemuOpts and add share property >> Add kvm_eventfds_enabled function >> Add chardev API qemu_chr_fe_read_all >> Add chardev API qemu_chr_fe_set_msgfds >> Add chardev API qemu_chr_fe_get_msgfds >> Add G_IO_HUP handler for socket chardev >> vhost_net should call the poll callback only when it is set >> Refactor virtio-net to use generic get_vhost_net >> Add new virtio API virtio_queue_get_avail_idx >> Gracefully handle ioctl failure in vhost_virtqueue_stop >> vhost_net_init will use VhostNetOptions to get all its arguments >> Add vhost_ops to vhost_dev struct and replace all relevant ioctls >> Add mandatory_features to vhost_dev >> Add vhost-backend and VhostBackendType >> Add vhost-user as a vhost backend. >> Add new vhost-user netdev backend >> Add the vhost-user netdev backend to the command line >> Add vhost-user protocol documentation >> libqemustub: add stubs to be able to use qemu-char.c >> Add qtest for vhost-user >> >> docs/specs/vhost-user.txt | 261 ++++++++++++++++++++++++++++ >> exec.c | 21 ++- >> hmp-commands.hx | 4 +- >> hw/net/vhost_net.c | 141 ++++++++++----- >> hw/net/virtio-net.c | 29 +--- >> hw/scsi/vhost-scsi.c | 20 ++- >> hw/virtio/Makefile.objs | 2 +- >> hw/virtio/vhost-backend.c | 71 ++++++++ >> hw/virtio/vhost-user.c | 356 ++++++++++++++++++++++++++++++ >> ++++++++ >> hw/virtio/vhost.c | 58 +++---- >> hw/virtio/virtio.c | 5 + >> include/exec/cpu-all.h | 1 - >> include/hw/virtio/vhost-backend.h | 38 ++++ >> include/hw/virtio/vhost.h | 9 +- >> include/hw/virtio/virtio.h | 1 + >> include/net/vhost-user.h | 17 ++ >> include/net/vhost_net.h | 13 +- >> include/sysemu/char.h | 43 ++++- >> include/sysemu/kvm.h | 11 ++ >> kvm-all.c | 4 + >> kvm-stub.c | 1 + >> net/Makefile.objs | 2 +- >> net/clients.h | 3 + >> net/hub.c | 1 + >> net/net.c | 25 +-- >> net/tap.c | 18 +- >> net/vhost-user.c | 273 +++++++++++++++++++++++++++++ >> qapi-schema.json | 19 +- >> qemu-char.c | 272 +++++++++++++++++++++++++---- >> qemu-options.hx | 25 ++- >> stubs/Makefile.objs | 8 + >> stubs/bdrv-commit-all.c | 7 + >> stubs/chr-msmouse.c | 7 + >> stubs/get-next-serial.c | 3 + >> stubs/is-daemonized.c | 7 + >> stubs/machine-init-done.c | 6 + >> stubs/monitor-init.c | 6 + >> stubs/notify-event.c | 6 + >> stubs/vc-init.c | 7 + >> tests/Makefile | 4 + >> tests/vhost-user-test.c | 309 ++++++++++++++++++++++++++++++ >> +++ >> vl.c | 23 ++- >> 42 files changed, 1979 insertions(+), 158 deletions(-) >> create mode 100644 docs/specs/vhost-user.txt >> create mode 100644 hw/virtio/vhost-backend.c >> create mode 100644 hw/virtio/vhost-user.c >> create mode 100644 include/hw/virtio/vhost-backend.h >> create mode 100644 include/net/vhost-user.h >> create mode 100644 net/vhost-user.c >> create mode 100644 stubs/bdrv-commit-all.c >> create mode 100644 stubs/chr-msmouse.c >> create mode 100644 stubs/get-next-serial.c >> create mode 100644 stubs/is-daemonized.c >> create mode 100644 stubs/machine-init-done.c >> create mode 100644 stubs/monitor-init.c >> create mode 100644 stubs/notify-event.c >> create mode 100644 stubs/vc-init.c >> create mode 100644 tests/vhost-user-test.c >> >> > -- Antonios Motakis Virtual Open Systems
