Re: Design doc of adding ACPI support for arm64 on Xen - version 2

[Ian Campbell <ian.campbell@citrix.com>]

On Wed, 2015-08-12 at 10:47 +0800, Shannon Zhao wrote:
> 
> On 2015/8/11 23:52, Boris Ostrovsky wrote:
> > On 08/11/2015 11:35 AM, Ian Campbell wrote:
> > > On Tue, 2015-08-11 at 11:29 -0400, Boris Ostrovsky wrote:
> > > > On 08/11/2015 10:21 AM, Ian Campbell wrote:
> > > > > On Tue, 2015-08-11 at 15:19 +0100, Ian Campbell wrote:
> > > > > > On Fri, 2015-08-07 at 10:11 +0800, Shannon Zhao wrote:
> > > > > > > This document is going to explain the design details of Xen 
> > > > > > > booting
> > > > > > > with
> > > > > > > ACPI on ARM. Maybe parts of it may not be appropriate. Any 
> > > > > > > comments
> > > > > > > are
> > > > > > > welcome.
> > > > > > Some small subsets of this seem like they might overlap with 
> > > > > > what
> > > > > > will be
> > > > > > required for PVH on x86 (a new x86 guest mode not dissimilar to 
> > > > > > the
> > > > > > sole
> > > > > > ARM guest mode). If so then it would be preferable IMHO if PVH 
> > > > > > x86
> > > > > > could
> > > > > > use the same interfaces.
> > > > > > 
> > > > > > I've trimmed the quotes to just those bits and CCd some of the 
> > > > > > PVH
> > > > > > people
> > > > > > (Boris and Roger[0]) in case they have any thoughts.
> > > > > > 
> > > > > > Actually, having done the trimming there is only one such bit:
> > > > > > 
> > > > > > [...]
> > > > > > > 4. Map MMIO regions
> > > > > > > -------------------
> > > > > > > Register a bus_notifier for platform and amba bus in Linux.
> > > > > Previously PCI was included in this scheme, which is why I 
> > > > > thought of
> > > > > PVH,
> > > > > having missed that PCI wasn't mentioned here now.
> > > > > 
> > > > > Is it handled some other way now or is that just an accidental
> > > > > omission?
> > > > PCI already has a bus notifier which is probably why it's not 
> > > > explicitly
> > > > called out here.
> > > Right, but I was more specifically thinking of the bit which followed
> > > regarding the use of the notifier to map the MMIO, which is the more
> > > important bit.
> > 
> > This notifier calls PHYSDEVOP_pci_device_add and as far as I can tell
> > MMIO is mapped there (for IOMMU, which IIUIC is the main issue here).
> 
> Right, at this moment we only add platform and amba bus bus_notifier.
> The PCI device can reuse existing bus_notifier.

Super. Perhaps add a sentence to that effect so I remember that this
already exists next time?