From 8e62b2af62ea165f6bb7dbd1128ed1542a63eb6b Mon Sep 17 00:00:00 2001 From: Longpeng Date: Sat, 12 Nov 2022 22:40:13 +0800 Subject: [PATCH 6/7] docs: Add generic vhost-vdpa device documentation Signed-off-by: Longpeng --- docs/system/device-emulation.rst | 1 + .../devices/vhost-vdpa-generic-device.rst | 46 +++++++++++++++++++ 2 files changed, 47 insertions(+) create mode 100644 docs/system/devices/vhost-vdpa-generic-device.rst diff --git a/docs/system/device-emulation.rst b/docs/system/device-emulation.rst index 19944f526c..ef299a2fcd 100644 --- a/docs/system/device-emulation.rst +++ b/docs/system/device-emulation.rst @@ -89,3 +89,4 @@ Emulated Devices devices/vhost-user.rst devices/virtio-pmem.rst devices/vhost-user-rng.rst + devices/vhost-vdpa-generic-device.rst diff --git a/docs/system/devices/vhost-vdpa-generic-device.rst b/docs/system/devices/vhost-vdpa-generic-device.rst new file mode 100644 index 0000000000..25fbcac60e --- /dev/null +++ b/docs/system/devices/vhost-vdpa-generic-device.rst @@ -0,0 +1,46 @@ + +========================= +vhost-vDPA generic device +========================= + +This document explains the usage of the vhost-vDPA generic device. + +Description +----------- + +vDPA(virtio data path acceleration) device is a device that uses a datapath +which complies with the virtio specifications with vendor specific control +path. + +QEMU provides two types of vhost-vDPA devices to enable the vDPA device, one +is type sensitive which means QEMU needs to know the actual device type +(e.g. net, blk, scsi) and another is called "vhost-vDPA generic device" which +is type insensitive + +The vhost-vDPA generic device builds on the vhost-vdpa subsystem and virtio +subsystem. It is quite small, but it can support any type of virtio device. + +Examples +-------- + +Prepare the vhost-vDPA backends first: + +:: + host# ls -l /dev/vhost-vdpa-* + crw------- 1 root root 236, 0 Nov 2 00:49 /dev/vhost-vdpa-0 + +Start QEMU with virtio-mmio bus: + +:: + host# qemu-system \ + -M microvm -m 512 -smp 2 -kernel ... -initrd ... \ + -device vhost-vdpa-device,vhostdev=/dev/vhost-vdpa-0 \ + ... + +Start QEMU with virtio-pci bus: + +:: + host# qemu-system \ + -M pc -m 512 -smp 2 \ + -device vhost-vdpa-device-pci,vhostdev=/dev/vhost-vdpa-0 \ + ...\ -- 2.27.0