c8a6153b - vduse: Introduce VDUSE - vDPA Device in Userspace

Tue, 31 Aug 2021 10:36:33 +0000

vduse: Introduce VDUSE - vDPA Device in UserspaceThis VDUSE driver enables implementing software-emulated vDPAdevices in userspace. The vDPA device is created byioctl(VDUSE_CREATE_DEV) on /dev/vduse/control. Then a char deviceinterface (/dev/vduse/$NAME) is exported to userspace for deviceemulation.In order to make the device emulation more secure, the device'scontrol path is handled in kernel. A message mechnism is introducedto forward some dataplane related control messages to userspace.And in the data path, the DMA buffer will be mapped into userspaceaddress space through different ways depending on the vDPA bus towhich the vDPA device is attached. In virtio-vdpa case, the MMU-basedsoftware IOTLB is used to achieve that. And in vhost-vdpa case, theDMA buffer is reside in a userspace memory region which can be sharedto the VDUSE userspace processs via transferring the shmfd.For more details on VDUSE design and usage, please see the follow-onDocumentation commit.NB(mst): when merging this withb542e383d8c0 ("eventfd: Make signal recursion protection a task bit")replace eventfd_signal_count with eventfd_signal_allowed,and drop the previous("eventfd: Export eventfd_wake_count to modules").Signed-off-by: Xie Yongji Acked-by: Jason Wang Link: https://lore.kernel.org/r/20210831103634.33-13-xieyongji@bytedance.comSigned-off-by: Michael S. Tsirkin List of files: /linux-6.15/drivers/vdpa/vdpa_user/Makefile

Changes in Makefile

c8a6153b - vduse: Introduce VDUSE - vDPA Device in Userspace