Re: [Qemu-devel] [Xen-devel] [PATCH v3] Hvmloader: Modify ACPI to only supply _EJ0 methods for PCIslots that support hotplug by runtime patching

[Michael S. Tsirkin]

On Thu, May 08, 2014 at 12:26:21PM +0100, Ian Campbell wrote:
> On Thu, 2014-05-08 at 07:29 +0000, Gonglei (Arei) wrote:
> >  > +        rmvc_pcrm = inl(PCI_RMV_BASE);
> > > >
> > > >
> > > > So .. what is at this special 0xae0c address?
> > > >
> > > > Is there some code in QEMU that needs this treatment as well?
> > > >
> > Yep, the 0xae0c is defined in upstream QEMU, which show the hotplugging 
> > ability 
> > of PCI devices. 
> 
> Is this considered to be a ABI by qemu? Or is it subject to change?
> 
> How is this going to interact with
> http://lists.xen.org/archives/html/xen-devel/2014-05/msg00026.html ? (At
> leas then it is a Xen interface I suppose)
> 
> Ian.

This is the ABI guarantee:
There's a file (exposed with fwcfg file interface to guests)
named etc/table-loader.
If present, this file includes a list of other fwcfg files
including available acpi tables (can be multiple acpi tables per file)
together with some extra information helpful for guests
(checksum location and pointers from one table to another).

-- 
MST