Porting the block-iscsi hotplug script

[Gustau Pérez]

El 26/02/16 a les 11:26, Roger Pau Monné ha escrit:
> Hello,
>
> I've rebased everything on top of Xen 4.5, so it can be applied to the
> xen-tools and xen-kernel packages without issues, I've uploaded all the
> patches to:
>
> https://people.freebsd.org/~royger/hotplug/

   So in my case, I'd need those patches and the patches at [1] (or the
machine would panic at the ata stage during the boot), wouldn't I? I
don't know if I'll be able to deal with that today or this weekend, if
not monday I'll test and let you know.

> As you can see, each folder contains the patches that should be applied
> to each component. With this I've been able to use the simple block
> hotplug script that's included in the series.
>
> There's a limitation with block hotplug scripts, that is not specific to
> FreeBSD (the same applies to Linux for example). You cannot use block
> hotplug scripts with HVM guests. This is because HVM guests require a
> QEMU instance, and in order to provide a virtual disk to QEMU it must be
> a file or block device present on the system. Then when using block
> hotplug scripts the block device can only be made available using what
> we call a local attach (attaching the virtual disk to Dom0), and libxl
> doesn't do that yet. Of course patches are very welcome to remove this
> limitation ;). The code to perform local attaching to Dom0 is already in
> libxl, it's just not used for this case.
>
> Roger.

   In fact this is the scenario I'm most interested in :) I'll first
take a took a the current situation with PV guests and build that
hotplug script and then I think I'd like to deal with the support for
HVM guests.

   Thank you,

   Gustau

[1] https://people.freebsd.org/~royger/xen_ins/