| Message ID | 20180110091846.10699-9-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | block: Add VFIO based driver for NVMe device | expand |
On Wed, Jan 10, 2018 at 05:18:45PM +0800, Fam Zheng wrote: > 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. The text dives straight into vfio-pci without any explanation of this feature. Please include something like: NVM Express (NVMe) storage controllers can be accessed directly by a userspace driver in QEMU. This bypasses the host kernel file system and block layers while retaining QEMU block layer functionality, such as block jobs, I/O throttling, etc. Disk I/O performance is typically higher than with -drive file=/dev/sda. > +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. I suggest moving this up to the beginning in the hopes that people will read it before asking questions on IRC or qemu-devel :).
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
Signed-off-by: Fam Zheng <famz@redhat.com> --- docs/qemu-block-drivers.texi | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)