Re: [edk2] Passing Xen memory map and resource map to OVMF

From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: Wei Liu <wei.liu2@citrix.com>,
	"Jordan Justen (Intel address)" <jordan.l.justen@intel.com>,
	edk2-devel@lists.sourceforge.net, xen-devel@lists.xen.org,
	Igor Mammedov <imammedo@redhat.com>,
	Laszlo Ersek <lersek@redhat.com>
Subject: Re: [edk2] Passing Xen memory map and resource map to OVMF
Date: Wed, 13 Nov 2013 11:51:22 -0500	[thread overview]
Message-ID: <20131113165122.GL2793@phenom.dumpdata.com> (raw)
In-Reply-To: <1384350814.3560.24.camel@nilsson.home.kraxel.org>

On Wed, Nov 13, 2013 at 02:53:34PM +0100, Gerd Hoffmann wrote:
> On Mi, 2013-11-13 at 11:58 +0000, Wei Liu wrote:
> > On Wed, Nov 13, 2013 at 08:03:39AM +0100, Gerd Hoffmann wrote:
> > >   Hi,
> > > 
> > > > > The first thing that comes in mind is to reuse E820 table for memory map
> > > > > plus some extra fields for io / mmio resources. But I guess UEFI is the
> > > > > new world so stuffs like E820 from old world will be less popular. Any
> > > > > suggestion on existing table / data structure I can use?
> > > 
> > > What io/mmio ressources do you need to pass on?
> > > 
> > 
> > MMIO holes, IO range created by hvmloader.
> 
> Why?  All (memory) address space not backed by ram effectively is mmio.
> There is no need to explicitly declare holes ...

That is the case.

The question is where should RAM start and stop. And if you want to
extend the MMIO (for odd cards that you are passing in.

> 
> Also why io ranges?  Isn't pc io address space pretty much fixed anyway?

I think most BIOSes mark that area as E820_RSV?

 000000000009e800 - 00000000000a0000 (reserved)

Oh wait, that is not PC IO address. You are right those are
most certainly marked as normal RAM.

> 
> cheers,
>   Gerd
> 
> 
> 
> 
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