Re: [MirageOS-devel] xen and multiple block devices

[Dave Scott <Dave.Scott@xxxxxxxxxx>]

> On Jan 28, 2014, at 12:35 PM, "Richard Mortier" 
> <Richard.Mortier@xxxxxxxxxxxxxxxx> wrote:
> 
> 
>> On 28 Jan 2014, at 12:13, David Scott <scott.dj@xxxxxxxxx> wrote:
>> ...
>> So in mirage-skeleton/basic_block/config.ml you can change the line to:
>> 
>>  let block = block_of_file "/dev/loop0" in
>> 
>> and then your VM console will have lines like:
>> 
>> Block.connect /dev/loop0: interpreting /dev/loop0 as a backend params key, 
>> translating to 51712
>> Block.connect /dev/loop0 -> 51712
>> Blkfront.create; vdev=51712
> 
> thanks :)
> 
> out of curiosity, are there any constraints on the "/dev/loop0" parameter, or 
> is it just an opaque key string?

/dev/loop0 has to be the backing storage mentioned in your .xl file. Xl will 
put the key in xenstore and Linux kernel blkback (via some horrific udev mess 
that you don't want to know about) will open / read / write.

You can write normal file names in the .xl file, which xl should magically 
handle. On my Debian laptop it's broken, but I was hoping that if we used the 
raw file name then it would work under both xen and unix transparently.This may 
require a bit more tweaking to strip off any prefix which xl might add (like 
"aio:")

Anyway, let me know if this helps.

In future I'd also like to add support for "connecting" to a labelled 
partition, which would help lift us out of this particular rathole altogether 
:-)

Cheers,
Dave
> 
> -- 
> Cheers,
> 
> R.
> 
> 
> 
> 
> This message and any attachment are intended solely for the addressee and may 
> contain confidential information. If you have received this message in error, 
> please send it back to me, and immediately delete it.   Please do not use, 
> copy or disclose the information contained in this message or in any 
> attachment.  Any views or opinions expressed by the author of this email do 
> not necessarily reflect the views of the University of Nottingham.
> 
> This message has been checked for viruses but the contents of an attachment
> may still contain software viruses which could damage your computer system, 
> you are advised to perform your own checks. Email communications with the 
> University of Nottingham may be monitored as permitted by UK legislation.
> 
> 
> 
> 
> 
> _______________________________________________
> MirageOS-devel mailing list
> MirageOS-devel@xxxxxxxxxxxxxxxxxxxx
> http://lists.xenproject.org/cgi-bin/mailman/listinfo/mirageos-devel

_______________________________________________
MirageOS-devel mailing list
MirageOS-devel@xxxxxxxxxxxxxxxxxxxx
http://lists.xenproject.org/cgi-bin/mailman/listinfo/mirageos-devel