From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from [140.186.70.92] (port=33088 helo=eggs.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1PQOkP-0001sJ-1K
	for qemu-devel@nongnu.org; Wed, 08 Dec 2010 13:28:14 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <lcapitulino@redhat.com>) id 1PQOkN-0005d6-ED
	for qemu-devel@nongnu.org; Wed, 08 Dec 2010 13:28:12 -0500
Received: from mx1.redhat.com ([209.132.183.28]:60410)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <lcapitulino@redhat.com>) id 1PQOkN-0005ch-6g
	for qemu-devel@nongnu.org; Wed, 08 Dec 2010 13:28:11 -0500
Date: Wed, 8 Dec 2010 16:27:45 -0200
From: Luiz Capitulino <lcapitulino@redhat.com>
Message-ID: <20101208162745.60d085db@doriath>
In-Reply-To: <4CFFCD10.6060500@linux.vnet.ibm.com>
References: <20101208160110.1b0c7c64@doriath>
	<4CFFCD10.6060500@linux.vnet.ibm.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Subject: [Qemu-devel] Re: [PATCH] Fix segfault with ram_size > 4095M without
	kvm
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.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: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Anthony Liguori <aliguori@linux.vnet.ibm.com>
Cc: ryanh@linux.vnet.ibm.com, amit.shah@redhat.com, Anthony Liguori <aliguori@us.ibm.com>, qemu-devel@nongnu.org, aurelien@aurel32.net

On Wed, 08 Dec 2010 12:23:12 -0600
Anthony Liguori <aliguori@linux.vnet.ibm.com> wrote:

> On 12/08/2010 12:01 PM, Luiz Capitulino wrote:
> > Currently, x86_64-softmmu qemu segfaults when trying to use>  4095M memsize.
> > This patch adds a simple check and error message (much like the 2047 limit on
> > 32-bit hosts) on ram_size in the control path after we determine we're
> > not using kvm
> >
> > Upstream qemu-kvm is affected if using the -no-kvm option; this patch address
> > the segfault there as well.
> >
> > Signed-off-by: Ryan Harper<ryanh@us.ibm.com>
> > Signed-off-by: Aurelien Jarno<aurelien@aurel32.net>
> > ---
> > NOTE: this patch was applied in the v0.12.x branch, but it seems it got
> >        lost for master
> >    
> 
> No, it was intentional.  We should fix the segv, this is not a known 
> limitation but rather a bug.

A TCG bug, I presume?

> 
> Regards,
> 
> Anthony Liguori
> 
> >   vl.c |    6 ++++++
> >   1 files changed, 6 insertions(+), 0 deletions(-)
> >
> > diff --git a/vl.c b/vl.c
> > index 2dbb6db..bb9c21c 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -5792,6 +5792,12 @@ int main(int argc, char **argv, char **envp)
> >               fprintf(stderr, "failed to initialize KVM\n");
> >               exit(1);
> >           }
> > +    } else {
> > +        /* without kvm enabled, we can only support 4095 MB RAM */
> > +        if (ram_size>  (4095UL<<  20)) {
> > +            fprintf(stderr, "qemu: without kvm support at most 4095 MB RAM can be simulated\n");
> > +            exit(1);
> > +        }
> >       }
> >
> >       if (qemu_init_main_loop()) {
> >    
>