From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:49414)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <agraf@suse.de>) id 1X9Xms-0000DG-8j
	for qemu-devel@nongnu.org; Tue, 22 Jul 2014 06:59:20 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <agraf@suse.de>) id 1X9Xmm-00079B-3T
	for qemu-devel@nongnu.org; Tue, 22 Jul 2014 06:59:14 -0400
Message-ID: <53CE43F9.6010403@suse.de>
Date: Tue, 22 Jul 2014 12:59:05 +0200
From: Alexander Graf <agraf@suse.de>
MIME-Version: 1.0
References: <1405935017-15390-1-git-send-email-hutao@cn.fujitsu.com>
In-Reply-To: <1405935017-15390-1-git-send-email-hutao@cn.fujitsu.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH for 2.1] ppc: fix -mem-path failure
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: Hu Tao <hutao@cn.fujitsu.com>
Cc: "Shreyas B. Prabhu" <shreyas@linux.vnet.ibm.com>, "<qemu-ppc@nongnu.org>" <qemu-ppc@nongnu.org>, qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>

On 07/21/2014 11:30 AM, Hu Tao wrote:
> commit e938ba0c tried to enable -mem-path for ppc but breaked some ppc
> boards.
>
> The problems are:
>
> 1. it fails when allocating memory for rom, sram whose sizes are less
>     than huge page size:
>
>     ./ppc-softmmu/qemu-system-ppc  -m 512 -mem-path /hugepages/ \
>     -kernel /home/hutao/Downloads/vmlinux-ppc -initrd \
>     /home/hutao/Downloads/initrd-ppc.gz
>     qemu-system-ppc: /mnt/data/projects/qemu/exec.c:1184: qemu_ram_set_idstr: Assertion `new_block' failed.
>
> 2. if there is a numa node backed by memory backend object, qemu fails
>     with message:
>
>     ./ppc-softmmu/qemu-system-ppc  -m 512 \
>     -object memory-backend-file,size=512M,mem-path=/hugepages,id=f0 \
>     -numa node,nodeid=0,memdev=f0 \
>     -kernel /home/hutao/Downloads/vmlinux-ppc \
>     -initrd /home/hutao/Downloads/initrd-ppc.gz
>     qemu-system-ppc: memory backend f0 is used multiple times. Each -numa option must use a different memdev value.
>
> This patch does following:
>
> 1. replaces memory_region_allocate_system_memory() with
>     memory_region_init_ram() for rom, sram. Then only system memory
>     is backed by hugepages when specifying mem-path.
>
> 2. for memory banks, allocates all ram with
>     one memory_region_allocate_system_memory(), and use
>     memory_region_init_alias() to initialize memory banks.
>
> Tested machines: default(g3beige), mac99, taihu, bamboo, ref405ep.
>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>

Thanks, this makes a lot of sense.

I've applied this to ppc-next (for 2.1) and kicked off an autotest run. 
If that's successful, I'll send a pull request to Peter ASAP.


Alex