Jason Wang
2020-Dec-23 06:38 UTC
[RFC v2 00/13] Introduce VDUSE - vDPA Device in Userspace
On 2020/12/22 ??10:52, Xie Yongji wrote:> This series introduces a framework, which can be used to implement > vDPA Devices in a userspace program. The work consist of two parts: > control path forwarding and data path offloading. > > In the control path, the VDUSE driver will make use of message > mechnism to forward the config operation from vdpa bus driver > to userspace. Userspace can use read()/write() to receive/reply > those control messages. > > In the data path, the core is mapping dma buffer into VDUSE > daemon's address space, which can be implemented in different ways > depending on the vdpa bus to which the vDPA device is attached. > > In virtio-vdpa case, we implements a MMU-based on-chip IOMMU driver with > bounce-buffering mechanism to achieve that.Rethink about the bounce buffer stuffs. I wonder instead of using kernel pages with mmap(), how about just use userspace pages like what vhost did? It means we need a worker to do bouncing but we don't need to care about annoying stuffs like page reclaiming?> And in vhost-vdpa case, the dma > buffer is reside in a userspace memory region which can be shared to the > VDUSE userspace processs via transferring the shmfd. > > The details and our user case is shown below: > > ------------------------ ------------------------- ---------------------------------------------- > | Container | | QEMU(VM) | | VDUSE daemon | > | --------- | | ------------------- | | ------------------------- ---------------- | > | |dev/vdx| | | |/dev/vhost-vdpa-x| | | | vDPA device emulation | | block driver | | > ------------+----------- -----------+------------ -------------+----------------------+--------- > | | | | > | | | | > ------------+---------------------------+----------------------------+----------------------+--------- > | | block device | | vhost device | | vduse driver | | TCP/IP | | > | -------+-------- --------+-------- -------+-------- -----+---- | > | | | | | | > | ----------+---------- ----------+----------- -------+------- | | > | | virtio-blk driver | | vhost-vdpa driver | | vdpa device | | | > | ----------+---------- ----------+----------- -------+------- | | > | | virtio bus | | | | > | --------+----+----------- | | | | > | | | | | | > | ----------+---------- | | | | > | | virtio-blk device | | | | | > | ----------+---------- | | | | > | | | | | | > | -----------+----------- | | | | > | | virtio-vdpa driver | | | | | > | -----------+----------- | | | | > | | | | vdpa bus | | > | -----------+----------------------+---------------------------+------------ | | > | ---+--- | > -----------------------------------------------------------------------------------------| NIC |------ > ---+--- > | > ---------+--------- > | Remote Storages | > ------------------- > > We make use of it to implement a block device connecting to > our distributed storage, which can be used both in containers and > VMs. Thus, we can have an unified technology stack in this two cases. > > To test it with null-blk: > > $ qemu-storage-daemon \ > --chardev socket,id=charmonitor,path=/tmp/qmp.sock,server,nowait \ > --monitor chardev=charmonitor \ > --blockdev driver=host_device,cache.direct=on,aio=native,filename=/dev/nullb0,node-name=disk0 \ > --export vduse-blk,id=test,node-name=disk0,writable=on,vduse-id=1,num-queues=16,queue-size=128 > > The qemu-storage-daemon can be found at https://github.com/bytedance/qemu/tree/vduse > > Future work: > - Improve performance (e.g. zero copy implementation in datapath) > - Config interrupt support > - Userspace library (find a way to reuse device emulation code in qemu/rust-vmm) > > This is now based on below series: > https://lore.kernel.org/netdev/20201112064005.349268-1-parav at nvidia.com/ > > V1 to V2: > - Add vhost-vdpa supportI may miss something but I don't see any code to support that. E.g neither set_map nor dma_map/unmap is implemented in the config ops. Thanks> - Add some documents > - Based on the vdpa management tool > - Introduce a workqueue for irq injection > - Replace interval tree with array map to store the iova_map > > Xie Yongji (13): > mm: export zap_page_range() for driver use > eventfd: track eventfd_signal() recursion depth separately in different cases > eventfd: Increase the recursion depth of eventfd_signal() > vdpa: Remove the restriction that only supports virtio-net devices > vdpa: Pass the netlink attributes to ops.dev_add() > vduse: Introduce VDUSE - vDPA Device in Userspace > vduse: support get/set virtqueue state > vdpa: Introduce process_iotlb_msg() in vdpa_config_ops > vduse: Add support for processing vhost iotlb message > vduse: grab the module's references until there is no vduse device > vduse/iova_domain: Support reclaiming bounce pages > vduse: Add memory shrinker to reclaim bounce pages > vduse: Introduce a workqueue for irq injection > > Documentation/driver-api/vduse.rst | 91 ++ > Documentation/userspace-api/ioctl/ioctl-number.rst | 1 + > drivers/vdpa/Kconfig | 8 + > drivers/vdpa/Makefile | 1 + > drivers/vdpa/vdpa.c | 2 +- > drivers/vdpa/vdpa_sim/vdpa_sim.c | 3 +- > drivers/vdpa/vdpa_user/Makefile | 5 + > drivers/vdpa/vdpa_user/eventfd.c | 229 ++++ > drivers/vdpa/vdpa_user/eventfd.h | 48 + > drivers/vdpa/vdpa_user/iova_domain.c | 517 ++++++++ > drivers/vdpa/vdpa_user/iova_domain.h | 103 ++ > drivers/vdpa/vdpa_user/vduse.h | 59 + > drivers/vdpa/vdpa_user/vduse_dev.c | 1373 ++++++++++++++++++++ > drivers/vhost/vdpa.c | 34 +- > fs/aio.c | 3 +- > fs/eventfd.c | 20 +- > include/linux/eventfd.h | 5 +- > include/linux/vdpa.h | 11 +- > include/uapi/linux/vdpa.h | 1 + > include/uapi/linux/vduse.h | 119 ++ > mm/memory.c | 1 + > 21 files changed, 2598 insertions(+), 36 deletions(-) > create mode 100644 Documentation/driver-api/vduse.rst > create mode 100644 drivers/vdpa/vdpa_user/Makefile > create mode 100644 drivers/vdpa/vdpa_user/eventfd.c > create mode 100644 drivers/vdpa/vdpa_user/eventfd.h > create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c > create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h > create mode 100644 drivers/vdpa/vdpa_user/vduse.h > create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c > create mode 100644 include/uapi/linux/vduse.h >
Jason Wang
2020-Dec-23 08:14 UTC
[RFC v2 00/13] Introduce VDUSE - vDPA Device in Userspace
On 2020/12/23 ??2:38, Jason Wang wrote:>> >> V1 to V2: >> - Add vhost-vdpa support > > > I may miss something but I don't see any code to support that. E.g > neither set_map nor dma_map/unmap is implemented in the config ops. > > ThanksSpeak too fast :( I saw a new config ops was introduced. Let me dive into that. Thanks