[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] qemu virtIO blocking operation - question
From: |
Sinha, Ani |
Subject: |
Re: [Qemu-devel] qemu virtIO blocking operation - question |
Date: |
Tue, 13 Sep 2011 12:35:28 -0500 |
>>
>> We are trying to paravirtualize the IPMI device (/dev/ipmi0).
>
> From http://en.wikipedia.org/wiki/Intelligent_Platform_Management_Interface:
> "An implementation of IPMI version 1.5 can communicate via a direct
> serial connection or via a side-band local area network (LAN)
> connection to a remote client."
>
> Why do you need a new virtio device? Can't you use virtio-serial?
> This is what other management channels are using for host<->guest
> agents.
It might be possible. However, we are doing it this way because :
(a) I am not sure of the interactions with the real ipmi device on the host
when the device is shared with multiple guests (we are not using pci
passthrough to attach the device to a single guest). The device itself is
stateless - that is, it can not handle multiple requests at one time. When
multiple users use the device, the driver has to serialize the requests and
send it to the device. The existing ipmi driver within Linux
(drivers/char/ipmi) does that now. But this driver on one guest would not
know the existence of another guest. May be it might have to be reworked to
work with virtio-serial. Dunno.
So, we wanted to keep this driver as is in the host and build a lightweight
interface layer in the guest that can talk to the real driver on the host.
Multiple guests would then be like multiple processes accessing the device.
(b) We wanted to gain some experience paravirtualizing devices this way through
virtio since we have other proprietary hardware that needs to be
paravirtualized.
Makes sense?
Ani
============================================================
The information contained in this message may be privileged
and confidential and protected from disclosure. If the reader
of this message is not the intended recipient, or an employee
or agent responsible for delivering this message to the
intended recipient, you are hereby notified that any reproduction,
dissemination or distribution of this communication is strictly
prohibited. If you have received this communication in error,
please notify us immediately by replying to the message and
deleting it from your computer. Thank you. Tellabs
============================================================
Re: [Qemu-devel] qemu virtIO blocking operation - question, Sinha, Ani, 2011/09/12