From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:59299) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RE3CU-000649-4X for qemu-devel@nongnu.org; Wed, 12 Oct 2011 14:06:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RE3CS-0007jv-R3 for qemu-devel@nongnu.org; Wed, 12 Oct 2011 14:06:42 -0400 Received: from v220110690675601.yourvserver.net ([78.47.199.172]:57570) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RE3CS-0007iT-LX for qemu-devel@nongnu.org; Wed, 12 Oct 2011 14:06:40 -0400 Message-ID: <4E95D6F1.4070402@weilnetz.de> Date: Wed, 12 Oct 2011 20:05:37 +0200 From: Stefan Weil MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] 2 MiB alignment in qemu_vmalloc() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: QEMU Developers Hello Avi, commit 36b58628 increased the alignment for some large memory blocks (typically the system RAM) to 2 MiB (QEMU_VMALLOC_ALIGN) on x86_64 Linux hosts. As far as I know, this was only required for KVM. There is a bad side effect of this increase: the Valgrind tool only supports an alignment of up to 1 MiB. It aborts execution with current QEMU for any target (even non-KVM targets). It might be possible to modify Valgrind (as far as I know this is already discussed), and of course I can also patch my local QEMU. Nevertheless, I think the alignment should be reduced again when there is no KVM support or KVM is disabled. Maybe the large alignment has other unwanted side effects. The code is in oslib-posix.c (target independent) and needs something like kvm_enabled() (currently a macro). What would you suggest? Maybe you can provide a patch. Kind regards, Stefan