[Qemu-devel] [PATCH v4 8/9] docs: Add section for NVMe VFIO driver

[Fam Zheng <famz@redhat.com>]

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 docs/qemu-block-drivers.texi | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/docs/qemu-block-drivers.texi b/docs/qemu-block-drivers.texi
index 503c1847aa..66b27cc4f7 100644
--- a/docs/qemu-block-drivers.texi
+++ b/docs/qemu-block-drivers.texi
@@ -785,6 +785,38 @@ warning: ssh server @code{ssh.example.com:22} does not support fsync
 With sufficiently new versions of libssh2 and OpenSSH, @code{fsync} is
 supported.
 
+@node disk_images_nvme
+@subsection NVMe disk images
+
+You can access disk images on a NVMe controller with the built-in VFIO based
+NVMe driver. Before starting QEMU, bind the host NVMe controller to vfio-pci.
+For example:
+
+@example
+# modprobe vfio-pci
+# lspci -n -s 0000:06:0d.0
+06:0d.0 0401: 1102:0002 (rev 08)
+# echo 0000:06:0d.0 > /sys/bus/pci/devices/0000:06:0d.0/driver/unbind
+# echo 1102 0002 > /sys/bus/pci/drivers/vfio-pci/new_id
+
+# qemu-system-x86_64 -drive file=nvme://@var{host}:@var{bus}:@var{slot}.@var{func}/@var{namespace}
+@end example
+
+Alternative syntax using properties:
+
+@example
+qemu-system-x86_64 -drive file.driver=nvme,file.device=@var{host}:@var{bus}:@var{slot}.@var{func},file.namespace=@var{namespace}
+@end example
+
+@var{host}:@var{bus}:@var{slot}.@var{func} is the NVMe controller's PCI device
+address on the host.
+
+@var{namespace} is the NVMe namespace number, starting from 1.
+
+The controller will be exclusively used by the QEMU process once started. To be
+able to share storage between multiple VMs and other applications on the host,
+please use file based protocols.
+
 @node disk_image_locking
 @subsection Disk image file locking
 
-- 
2.14.3