From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=34696 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PQOnA-0003Xh-RF for qemu-devel@nongnu.org; Wed, 08 Dec 2010 13:31:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PQOn8-0006ID-Pf for qemu-devel@nongnu.org; Wed, 08 Dec 2010 13:31:04 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:37926) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PQOn8-0006I8-IR for qemu-devel@nongnu.org; Wed, 08 Dec 2010 13:31:02 -0500 Received: from d01dlp01.pok.ibm.com (d01dlp01.pok.ibm.com [9.56.224.56]) by e3.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id oB8I9chu022667 for ; Wed, 8 Dec 2010 13:13:02 -0500 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 65ABD728059 for ; Wed, 8 Dec 2010 13:31:01 -0500 (EST) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id oB8IV0uY445852 for ; Wed, 8 Dec 2010 13:31:01 -0500 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id oB8IUxTx019038 for ; Wed, 8 Dec 2010 11:31:00 -0700 Message-ID: <4CFFCEDE.6000502@linux.vnet.ibm.com> Date: Wed, 08 Dec 2010 12:30:54 -0600 From: Anthony Liguori MIME-Version: 1.0 References: <20101208160110.1b0c7c64@doriath> <4CFFCD10.6060500@linux.vnet.ibm.com> <20101208162745.60d085db@doriath> In-Reply-To: <20101208162745.60d085db@doriath> Content-Type: text/plain; charset=ISO-8859-1; format=flowed 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: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Luiz Capitulino Cc: ryanh@linux.vnet.ibm.com, amit.shah@redhat.com, qemu-devel@nongnu.org, aurelien@aurel32.net On 12/08/2010 12:27 PM, Luiz Capitulino wrote: > On Wed, 08 Dec 2010 12:23:12 -0600 > Anthony Liguori 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 >>> Signed-off-by: Aurelien Jarno >>> --- >>> 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? > Dunno, that's why we shouldn't just paper over it. Regards, Anthony Liguori > >> 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()) { >>> >>> >> >