From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1fXLKM-0001lk-LB for mharc-qemu-trivial@gnu.org; Mon, 25 Jun 2018 02:50:18 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33774) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fXLKH-0001iK-8u for qemu-trivial@nongnu.org; Mon, 25 Jun 2018 02:50:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fXLKG-0002dJ-Ah for qemu-trivial@nongnu.org; Mon, 25 Jun 2018 02:50:13 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:40620 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fXLKB-0002Xd-S7; Mon, 25 Jun 2018 02:50:07 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 91FEE8182D1F; Mon, 25 Jun 2018 06:50:06 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-145.ams2.redhat.com [10.36.116.145]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A24167C42; Mon, 25 Jun 2018 06:50:04 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 622D611385D6; Mon, 25 Jun 2018 08:50:03 +0200 (CEST) From: Markus Armbruster To: Paolo Bonzini Cc: Eduardo Habkost , Thomas Huth , zhang.zhanghailiang@huawei.com, Ben Warren , qemu-trivial@nongnu.org, Cornelia Huck , Markus Armbruster , qemu-devel@nongnu.org, Stefan Hajnoczi References: <1528866321-23886-5-git-send-email-thuth@redhat.com> <20180613133840.GK24528@stefanha-x1.localdomain> <20180613134452.GU19901@redhat.com> <20180613151942.GC19901@redhat.com> <87k1r24quk.fsf@dusky.pond.sub.org> <20180619171539.0adc90d6.cohuck@redhat.com> <20180622181108.GY7451@localhost.localdomain> <20180622193522.GI7451@localhost.localdomain> <743d495e-51cd-8c8e-293e-026b8dece74a@redhat.com> Date: Mon, 25 Jun 2018 08:50:03 +0200 In-Reply-To: <743d495e-51cd-8c8e-293e-026b8dece74a@redhat.com> (Paolo Bonzini's message of "Fri, 22 Jun 2018 23:22:43 +0200") Message-ID: <87lgb3xsv8.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 25 Jun 2018 06:50:06 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 25 Jun 2018 06:50:06 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'armbru@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: Re: [Qemu-trivial] [Qemu-devel] [RFC PATCH 4/4] qemu-options: Do not show -enable-kvm and -enable-hax in the docs anymore X-BeenThere: qemu-trivial@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Jun 2018 06:50:14 -0000 Paolo Bonzini writes: > On 22/06/2018 21:35, Eduardo Habkost wrote: >>>> Why is this better than using KVM by default if it's available? >>> The answer is (as almost always): Compatibility with migration. Nobody >>> dares to sacrifice that chicken :-( >> We can now kill it if we announce the feature as deprecated a >> couple of releases in advance. >> >> If we declare that compatibility when the accelerator is omitted >> is deprecated in 3.0, in QEMU 3.3 we will be free to choose a >> different default accelerator. > > We can, we don't necessarily want it. > > The status quo is that people using KVM are invoking qemu as qemu-kvm, > people using TCG are invoking qemu as qemu-system-*. All distros are > shipping a qemu-kvm or more rarely kvm binary, which is invariably a > wrapper script except for RHEL because RHEL doesn't have a qemu-system-* > binary at all. > > By the way, changing qemu-system-*'s default to e.g. RHEL's "kvm or tcg" > would not help distros that have "-accel kvm" in their /usr/bin/qemu-kvm > script. It wouldn't hurt them, either. Attentive distros could even replace the wrapper script by a link. > All in all, it seems simpler for me to take the status quo, which is > what non-RHEL distros do, and make it part of upstream. > > Paolo From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33750) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fXLKF-0001ek-6U for qemu-devel@nongnu.org; Mon, 25 Jun 2018 02:50:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fXLKB-0002YH-WB for qemu-devel@nongnu.org; Mon, 25 Jun 2018 02:50:11 -0400 From: Markus Armbruster References: <1528866321-23886-5-git-send-email-thuth@redhat.com> <20180613133840.GK24528@stefanha-x1.localdomain> <20180613134452.GU19901@redhat.com> <20180613151942.GC19901@redhat.com> <87k1r24quk.fsf@dusky.pond.sub.org> <20180619171539.0adc90d6.cohuck@redhat.com> <20180622181108.GY7451@localhost.localdomain> <20180622193522.GI7451@localhost.localdomain> <743d495e-51cd-8c8e-293e-026b8dece74a@redhat.com> Date: Mon, 25 Jun 2018 08:50:03 +0200 In-Reply-To: <743d495e-51cd-8c8e-293e-026b8dece74a@redhat.com> (Paolo Bonzini's message of "Fri, 22 Jun 2018 23:22:43 +0200") Message-ID: <87lgb3xsv8.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [RFC PATCH 4/4] qemu-options: Do not show -enable-kvm and -enable-hax in the docs anymore List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Eduardo Habkost , Thomas Huth , zhang.zhanghailiang@huawei.com, Ben Warren , qemu-trivial@nongnu.org, Cornelia Huck , Markus Armbruster , qemu-devel@nongnu.org, Stefan Hajnoczi Paolo Bonzini writes: > On 22/06/2018 21:35, Eduardo Habkost wrote: >>>> Why is this better than using KVM by default if it's available? >>> The answer is (as almost always): Compatibility with migration. Nobody >>> dares to sacrifice that chicken :-( >> We can now kill it if we announce the feature as deprecated a >> couple of releases in advance. >> >> If we declare that compatibility when the accelerator is omitted >> is deprecated in 3.0, in QEMU 3.3 we will be free to choose a >> different default accelerator. > > We can, we don't necessarily want it. > > The status quo is that people using KVM are invoking qemu as qemu-kvm, > people using TCG are invoking qemu as qemu-system-*. All distros are > shipping a qemu-kvm or more rarely kvm binary, which is invariably a > wrapper script except for RHEL because RHEL doesn't have a qemu-system-* > binary at all. > > By the way, changing qemu-system-*'s default to e.g. RHEL's "kvm or tcg" > would not help distros that have "-accel kvm" in their /usr/bin/qemu-kvm > script. It wouldn't hurt them, either. Attentive distros could even replace the wrapper script by a link. > All in all, it seems simpler for me to take the status quo, which is > what non-RHEL distros do, and make it part of upstream. > > Paolo