summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorXie Yongji <xieyongji@bytedance.com>2021-08-31 12:36:33 +0200
committerMichael S. Tsirkin <mst@redhat.com>2021-09-06 13:20:58 +0200
commitc8a6153b6c59d95c0e091f053f6f180952ade91e (patch)
tree549e205443878613acbc8a4f989a24c61fa540d9 /Documentation
parentvduse: Implement an MMU-based software IOTLB (diff)
downloadlinux-c8a6153b6c59d95c0e091f053f6f180952ade91e.tar.xz
linux-c8a6153b6c59d95c0e091f053f6f180952ade91e.zip
vduse: Introduce VDUSE - vDPA Device in Userspace
This VDUSE driver enables implementing software-emulated vDPA devices in userspace. The vDPA device is created by ioctl(VDUSE_CREATE_DEV) on /dev/vduse/control. Then a char device interface (/dev/vduse/$NAME) is exported to userspace for device emulation. In order to make the device emulation more secure, the device's control path is handled in kernel. A message mechnism is introduced to forward some dataplane related control messages to userspace. And in the data path, the DMA buffer will be mapped into userspace address space through different ways depending on the vDPA bus to which the vDPA device is attached. In virtio-vdpa case, the MMU-based software IOTLB is used to achieve that. 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. For more details on VDUSE design and usage, please see the follow-on Documentation commit. NB(mst): when merging this with b542e383d8c0 ("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 <xieyongji@bytedance.com> Acked-by: Jason Wang <jasowang@redhat.com> Link: https://lore.kernel.org/r/20210831103634.33-13-xieyongji@bytedance.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/userspace-api/ioctl/ioctl-number.rst1
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 1409e40e6345..293ca3aef358 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -300,6 +300,7 @@ Code Seq# Include File Comments
'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
'|' 00-7F linux/media.h
0x80 00-1F linux/fb.h
+0x81 00-1F linux/vduse.h
0x89 00-06 arch/x86/include/asm/sockios.h
0x89 0B-DF linux/sockios.h
0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range