From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46246) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c4tqa-0007LH-Co for qemu-devel@nongnu.org; Thu, 10 Nov 2016 13:13:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c4tqV-00074A-Nd for qemu-devel@nongnu.org; Thu, 10 Nov 2016 13:13:12 -0500 Received: from mail-wm0-x22a.google.com ([2a00:1450:400c:c09::22a]:37280) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1c4tqV-00073Q-Gi for qemu-devel@nongnu.org; Thu, 10 Nov 2016 13:13:07 -0500 Received: by mail-wm0-x22a.google.com with SMTP id t79so48382623wmt.0 for ; Thu, 10 Nov 2016 10:13:07 -0800 (PST) References: <20161109145748.27282-1-alex.bennee@linaro.org> <20161109145748.27282-20-alex.bennee@linaro.org> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: Date: Thu, 10 Nov 2016 18:13:04 +0000 Message-ID: <8760nv8aq7.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v6 19/19] tcg: enable MTTCG by default for ARM on x86 hosts List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson Cc: pbonzini@redhat.com, qemu-devel@nongnu.org, mttcg@greensocs.com, fred.konrad@greensocs.com, a.rigo@virtualopensystems.com, cota@braap.org, bobby.prani@gmail.com, nikunj@linux.vnet.ibm.com, mark.burton@greensocs.com, jan.kiszka@siemens.com, serge.fdrv@gmail.com, peter.maydell@linaro.org, claudio.fontana@huawei.com Richard Henderson writes: > On 11/09/2016 03:57 PM, Alex Bennée wrote: >> This enables the multi-threaded system emulation by default for ARMv7 >> and ARMv8 guests using the x86_64 TCG backend. This means: >> >> - The x86_64 TCG backend supports cmpxchg based atomic ops >> - The x86_64 TCG backend emits barriers for barrier ops > > What tcg backend doesn't support what we need? For a weakly ordered target, > any of our hosts should work. True, but this comes with certification that I've tested it. But you are right adding this to configure is fugly. Should I just drop the backend config symbol requirement totally? -- Alex Bennée