Re: [Qemu-devel] Question about xen disk unplug support for ahci missed in qemu

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

On Tue, 13 Oct 2015, John Snow wrote:
> On 10/13/2015 11:55 AM, Fabio Fantoni wrote:
> > I added ahci disk support in libxl and using it for week seems that was
> > ok, after a reply of Stefano Stabellini seems that xen disk unplug
> > support only ide disks:
> > http://git.qemu.org/?p=qemu.git;a=commitdiff;h=679f4f8b178e7c66fbc2f39c905374ee8663d5d8
> > 
> > Today Paul Durrant told me that even if pv disk is ok also with ahci and
> > the emulated one is offline can be a risk:
> > http://lists.xenproject.org/archives/html/win-pv-devel/2015-10/msg00021.html
> > 
> > 
> > I tried to take a fast look in qemu code but I not understand the needed
> > thing for add the xen disk unplug support also for ahci, can someone do
> > it or tell me useful information for do it please?
> > 
> > Thanks for any reply and sorry for my bad english.
> > 
> 
> I'm not entirely sure what features you need AHCI to support in order
> for Xen to be happy.
> 
> I'd guess hotplugging, but where I get confused is that IDE disks don't
> support hotplugging either, so I guess I'm not sure sure what you need.
> 
> Stefano, can you help bridge my Xen knowledge gap?
 
Hi John,

we need something like hw/i386/xen/xen_platform.c:unplug_disks but that
can unplug AHCI disk. And by unplug, I mean "make disappear" like
pci_piix3_xen_ide_unplug does for ide.