From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1N3Tu1-0007Sf-Hd
	for qemu-devel@nongnu.org; Thu, 29 Oct 2009 08:14:53 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1N3Ttx-0007Rt-Rt
	for qemu-devel@nongnu.org; Thu, 29 Oct 2009 08:14:53 -0400
Received: from [199.232.76.173] (port=57540 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1N3Ttx-0007Rl-KY
	for qemu-devel@nongnu.org; Thu, 29 Oct 2009 08:14:49 -0400
Received: from mx1.redhat.com ([209.132.183.28]:29470)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <mst@redhat.com>) id 1N3Ttx-000775-4J
	for qemu-devel@nongnu.org; Thu, 29 Oct 2009 08:14:49 -0400
Date: Thu, 29 Oct 2009 14:12:22 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20091029121221.GA3478@redhat.com>
References: <4ADED9A0.3000605@gmail.com> <4AE70C35.6050909@gmail.com>
	<20091027151640.GH5526@csclub.uwaterloo.ca>
	<4AE97CBA.80600@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
In-Reply-To: <4AE97CBA.80600@gmail.com>
Content-Transfer-Encoding: quoted-printable
Subject: [Qemu-devel] Re: Re: PCI address question
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: =?iso-8859-1?Q?M=E0rius_Mont=F3n?= <marius.monton@gmail.com>
Cc: qemu-devel@nongnu.org

On Thu, Oct 29, 2009 at 12:30:02PM +0100, M=E0rius Mont=F3n wrote:
> Lennart Sorensen wrote:
>=20
>     On Tue, Oct 27, 2009 at 04:05:25PM +0100, M=E0rius Mont=F3n wrote:
>=20
>=20
>         M=E0rius Mont=F3n wrote:
>=20
>=20
>             Hello,
>=20
>             For my PCI device to QEMU, I need the real address the PCI =
bus is using
>             to access my device. For a IO BAR (PCI_ADDRESS_SPACE_IO), I=
 receive the
>             real address (like 0xc200 or similar), but when registering=
 a
>             PCI_ADDRESS_SPACE_MEM I only receive the offset to the BAR.
>=20
>             How I can receive or obtaint the real address on each acces=
s to my device?
>=20
>             Cjeers,
>=20
>             M=E0rius
>=20
>=20
>=20
>         nobody can tell me anything? :(
>=20
>=20
>     Add the offset to the address in the bar?
>=20
> The problem is how to know what bar is accessing in case I have only on=
e
> function for all BARs.

I expect that's unusual: different BARs usually have different
functionality. Just implement different functions and pass
calls on to a shared helper?

>     After all the OS is allowed to change your BAR if it wants to.
>     So internally the only thing that makes sense to a PCI device is th=
e
>     offset from it's base address.
>=20
>     You listen to addresses at your IO range, and at your memory BAR ra=
nge.
>     What you do when you see a request for your range then depends on t=
he
>     offset that address had from the current base.  This would also be =
true
>     for the IO.
>=20
> I know all PCI internals, but I don't understand why for IO I receive a=
ll
> address and only the offset for MEM BARs (or I'm wrong?)
>=20
> M=E0rius

PCI only calls a map method. I think this gets a 32 bit address, not BAR =
offset:

               r->addr =3D new_addr;
               if (r->addr !=3D -1) {
                   r->map_func(d, i, r->addr, r->size, r->type);
               }


--=20
MST