From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59369) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNyTt-0005CU-Ax for qemu-devel@nongnu.org; Thu, 22 Jun 2017 05:32:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dNyTq-0005kU-8B for qemu-devel@nongnu.org; Thu, 22 Jun 2017 05:32:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58166) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dNyTq-0005kH-2n for qemu-devel@nongnu.org; Thu, 22 Jun 2017 05:32:50 -0400 References: <1498040401-16361-1-git-send-email-yang.zhong@intel.com> <1498040401-16361-2-git-send-email-yang.zhong@intel.com> <2c901b45-afb8-d807-19e9-14befbfdc3fd@redhat.com> <1082632418.11149315.1498112575500.JavaMail.zimbra@redhat.com> <666c9b73-843f-3669-fe1d-69b5082b2757@redhat.com> <8515dc9c-f632-cefa-fdf2-9fcbc8f962de@redhat.com> From: Paolo Bonzini Message-ID: <5eccb12a-cad3-95cb-6a6c-6f930e39f4eb@redhat.com> Date: Thu, 22 Jun 2017 11:32:46 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 01/15] configure: add the disable-tcg option List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: Yang Zhong , anthony xu , qemu-devel@nongnu.org, a rigo On 22/06/2017 11:30, Thomas Huth wrote: > On 22.06.2017 11:26, Paolo Bonzini wrote: >> >> >> On 22/06/2017 08:33, Thomas Huth wrote: >>> On 22.06.2017 08:22, Paolo Bonzini wrote: >>>> >>>>> On 21.06.2017 12:19, Yang Zhong wrote: >>>>>> Add the disable-tcg option into configure and echo CONFIG_TCG=y into >>>>>> $config_target_mak. The default tcg is enabled for all build. If tcg >>>>>> is disabled in the build, only i386|x86_64 softmmu option can be disabled, >>>>>> other softmmu of tagets and users build defaultly enabled the tcg. >>>>> Why do you want to limit this disablement to x86 only? There are also >>>>> other architectures that support KVM (ARM, PPC, MIPS), so disabling TCG >>>>> might be possible there, too. So I think it might be better to check >>>>> whether KVM is possible instead. >>>> >>>> You need to be careful and not use any helper from e.g. KVM or migration >>>> code. So I would be very surprised if any other architecture compiles >>>> with --disable-tcg. >>> >>> OK, fair, but we finally might want to get there, so I think we should >>> allow the parameter in the configure script for other architectures, >>> too, and then fix the bugs once we can try it out. >> >> I think it's the other way round---when someone wants to fix it, they >> should add their architecture to the list of targets that support >> --disable-tcg. "./configure ", as a goal, should fail >> immediately if make won't succeed; compilation errors are always a worse >> experience. > > Fine for me, too, but then the configure script should exit with a > proper error message when the user tried to specify --disable-tcg on a > non-x86 architecture. If I get the current patch right, it silently > falls back to CONFIG_TCG=y instead, which is IMHO also a bad experience. Yes, I agree. Thanks for reviewing the patch. Paolo