From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41296) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gTjWH-0005XG-Q8 for qemu-devel@nongnu.org; Mon, 03 Dec 2018 03:23:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gTjWC-0002dB-Mr for qemu-devel@nongnu.org; Mon, 03 Dec 2018 03:23:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60726) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gTjWC-0002c1-Fr for qemu-devel@nongnu.org; Mon, 03 Dec 2018 03:23:52 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9E48B3097074 for ; Mon, 3 Dec 2018 08:23:51 +0000 (UTC) From: Markus Armbruster References: <20181029125733.14597-1-marcandre.lureau@redhat.com> <20181029125733.14597-5-marcandre.lureau@redhat.com> Date: Mon, 03 Dec 2018 09:23:45 +0100 In-Reply-To: <20181029125733.14597-5-marcandre.lureau@redhat.com> (=?utf-8?Q?=22Marc-Andr=C3=A9?= Lureau"'s message of "Mon, 29 Oct 2018 16:57:31 +0400") Message-ID: <871s6z81da.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2 4/6] monitor: check if chardev can switch gcontext for OOB List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?utf-8?Q?Marc-Andr=C3=A9?= Lureau Cc: qemu-devel@nongnu.org, Paolo Bonzini , "Dr. David Alan Gilbert" , peterx@redhat.com Marc-Andr=C3=A9 Lureau writes: > Not all backends are able to switch gcontext. Those backends cannot > drive a OOB monitor (the monitor would then be blocking on main > thread). > > For example, ringbuf, spice, or more esoteric input chardevs like > braille or MUX. > > We currently forbid MUX because not all frontends are ready to run > outside main loop. Extend to add a context-switching feature check. Double-checking: the reason for forbidding MUX and the reason for requiring QEMU_CHAR_FEATURE_GCONTEXT are orthogonal, right? > Note: this patch will conflict with Peter "[PATCH v9 3/6] monitor: > remove "x-oob", turn oob on by default", but can be trivially updated. I intend to merge this series first, and drop this sentence. > Signed-off-by: Marc-Andr=C3=A9 Lureau > --- > monitor.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/monitor.c b/monitor.c > index 511dd11d1c..fffeb27ef9 100644 > --- a/monitor.c > +++ b/monitor.c > @@ -4560,9 +4560,11 @@ void monitor_init(Chardev *chr, int flags) > bool use_oob =3D flags & MONITOR_USE_OOB; >=20=20 > if (use_oob) { > - if (CHARDEV_IS_MUX(chr)) { > + if (CHARDEV_IS_MUX(chr) || > + !qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_GCONTEXT)) { > error_report("Monitor out-of-band is not supported with " > - "MUX typed chardev backend"); > + "%s typed chardev backend", > + object_get_typename(OBJECT(chr))); > exit(1); > } > if (use_readline) {