Re: [libvirt-users] If it's possible for a third-party PCIe card to be shared by multiple containers
Dear Daniel,
I found that lxc driver doesn't support hostdev with type of 'pci'.
As you mentioned before, I tried to expose the device node (the PCIe card) to the
container, my XML is as follow:
<devices>
<hostdev mode='subsystem' type='pci' managed='yes'>
<source>
<address bus='0x01' slot='0x00' function='0x0'/>
</source>
</hostdev>
</devices>
When I started the container, I got the error message:
Error: failed to start domain
Error: unsupported configuration: Unsupported hostdev type pci.
I want to confirm if the element hostdev of PCIe device is not supported by lxc driver
currently.
Have a nice day,
Cheng Wang
-----Original Message-----
From: Daniel P. Berrange [mailto:berrange@redhat.com]
Sent: 2014年1月16日 18:34
To: WANG Cheng D
Cc: libvirt-users(a)redhat.com
Subject: Re: [libvirt-users] If it's possible for a third-party PCIe card to be shared
by multiple containers
On Thu, Jan 16, 2014 at 08:55:53AM +0000, WANG Cheng D wrote:
Dear Daniel,
The thirty-party PCIe card is based on the Xilinx’ FPGA which is off the shelf, the main
features are as follows:
1) x8 Gen3, 8Gb/s per lane/direction
2) MSI and legacy interrupt support
3) Scatter-gather packet DMA engine provide by Northwest Logic We hope
multiple Linux Containers to access the PCIe card in time division mode, for example,
during slot 1, lxc1 read/write the PCIe card; during slot 2, lxc2 read/write the PCIe
card.
Taking reading operation (data flows from PCIe card to host memory) as example, in native
mode, the PCIe driver should tell PCIe card the host memory address where to store the
incoming data from PCIe card. With this address, the PCIe card will transmit the data to
host memory itself.
In container case, the problem is how application running in the container knows the
expected host memory address.
I wonder if we can have a process running in the which solely operates the PCIe card, all
the containers will send/receive data to this process via socket.
Ok, so from the LXC driver POV I guess this card is accessed via some special device node
with ioctls or something ? If so then you can just expose the device node to as many
containers as you like at the same time without restrictions.
http://libvirt.org/formatdomain.html#elementsHostDevCaps
Daniel
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