From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:44957)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <peter.maydell@linaro.org>) id 1YgCVN-0003U5-44
	for qemu-devel@nongnu.org; Thu, 09 Apr 2015 09:28:29 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <peter.maydell@linaro.org>) id 1YgCVI-0005Tl-Bu
	for qemu-devel@nongnu.org; Thu, 09 Apr 2015 09:28:25 -0400
Received: from mail-ig0-f179.google.com ([209.85.213.179]:38261)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <peter.maydell@linaro.org>) id 1YgCVI-0005Ta-5A
	for qemu-devel@nongnu.org; Thu, 09 Apr 2015 09:28:20 -0400
Received: by igbqf9 with SMTP id qf9so64340580igb.1
	for <qemu-devel@nongnu.org>; Thu, 09 Apr 2015 06:28:19 -0700 (PDT)
MIME-Version: 1.0
In-Reply-To: <20150409151718.5eb49015@nial.brq.redhat.com>
References: <1428055432-12120-1-git-send-email-zhaoshenglong@huawei.com>
	<1428055432-12120-11-git-send-email-zhaoshenglong@huawei.com>
	<877ftl1n4j.fsf@linaro.org>
	<20150409151718.5eb49015@nial.brq.redhat.com>
From: Peter Maydell <peter.maydell@linaro.org>
Date: Thu, 9 Apr 2015 14:27:58 +0100
Message-ID: <CAFEAcA-z0rDxfr_qAR=7uJ5jo6CuKxEtAEeq8B9SDgYhN6gHDQ@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Qemu-devel] [PATCH v4 10/20] hw/arm/virt-acpi-build: Generate
 RSDT table
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Igor Mammedov <imammedo@redhat.com>
Cc: hangaohuai@huawei.com, "Michael S. Tsirkin" <mst@redhat.com>, Alexander Spyridakis <a.spyridakis@virtualopensystems.com>, Mark Salter <msalter@redhat.com>, Claudio Fontana <claudio.fontana@huawei.com>, QEMU Developers <qemu-devel@nongnu.org>, Laszlo Ersek <lersek@redhat.com>, Hanjun Guo <hanjun.guo@linaro.org>, Shannon Zhao <zhaoshenglong@huawei.com>, Paolo Bonzini <pbonzini@redhat.com>, "Huangpeng (Peter)" <peter.huangpeng@huawei.com>, =?UTF-8?B?QWxleCBCZW5uw6ll?= <alex.bennee@linaro.org>, Christoffer Dall <christoffer.dall@linaro.org>, Shannon Zhao <shannon.zhao@linaro.org>

On 9 April 2015 at 14:17, Igor Mammedov <imammedo@redhat.com> wrote:
> On Thu, 09 Apr 2015 13:50:52 +0100
> Alex Benn=C3=A9e <alex.bennee@linaro.org> wrote:
>
>>
>> Shannon Zhao <zhaoshenglong@huawei.com> writes:
>> > +    for (i =3D 0; i < table_offsets->len; ++i) {
>> > +        /* rsdt->table_offset_entry to be filled by Guest linker */
>> > +        bios_linker_loader_add_pointer(linker,
>> > +                                       ACPI_BUILD_TABLE_FILE,
>> > +                                       ACPI_BUILD_TABLE_FILE,
>> > +                                       table_data, &rsdt->table_offse=
t_entry[i],
>> > +                                       sizeof(uint32_t));
>>
>> Why are these pointers always 32 bit? Can they ever be 64 bit?
> Laszlo, can you confirm that UEFI puts APCI tables below 4G address space=
?

In the general case you can't guarantee that there will
be any RAM at all below the 4G point. (The virt board
isn't like that, obviously, but I believe there's real
hardware out there that's designed that way.) I don't
think we should have any 32 bit assumptions in the
code at all -- pointer values should always be 64 bits
everywhere.

-- PMM