From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55250) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gUSlt-00079l-Uq for qemu-devel@nongnu.org; Wed, 05 Dec 2018 03:43:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gUSlp-0000kQ-Se for qemu-devel@nongnu.org; Wed, 05 Dec 2018 03:43:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45134) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gUSlp-0000hq-LI for qemu-devel@nongnu.org; Wed, 05 Dec 2018 03:43:01 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0682830001EF for ; Wed, 5 Dec 2018 08:43:01 +0000 (UTC) From: Markus Armbruster References: <20181204131802.16885-1-marcandre.lureau@redhat.com> <20181204131802.16885-5-marcandre.lureau@redhat.com> Date: Wed, 05 Dec 2018 09:42:55 +0100 In-Reply-To: <20181204131802.16885-5-marcandre.lureau@redhat.com> (=?utf-8?Q?=22Marc-Andr=C3=A9?= Lureau"'s message of "Tue, 4 Dec 2018 17:18:00 +0400") Message-ID: <874lbs1i0g.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 v3 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. > > 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 79afe99079..25cf4223e8 100644 > --- a/monitor.c > +++ b/monitor.c > @@ -4562,9 +4562,11 @@ 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) { Aha, this answers my question on the previous patch: yes, it is possible to trip the new assertion. Are there any ways other than this one? We could squash the two patches. But I figure you kept the previous patch separate on purpose. That's okay, but it should mention the assertion can be tripped, and the next patch (this one) will fix it.