From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1dno7w-0006dP-RO for mharc-qemu-trivial@gnu.org; Fri, 01 Sep 2017 11:45:00 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54069) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dno7q-0006NB-EK for qemu-trivial@nongnu.org; Fri, 01 Sep 2017 11:44:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dno7h-0004Fe-03 for qemu-trivial@nongnu.org; Fri, 01 Sep 2017 11:44:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53142) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dno7Z-0004Ar-TI; Fri, 01 Sep 2017 11:44:38 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C30D41F574; Fri, 1 Sep 2017 15:44:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C30D41F574 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=ehabkost@redhat.com Received: from localhost (ovpn-116-66.gru2.redhat.com [10.97.116.66]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9ADCD9568A; Fri, 1 Sep 2017 15:44:32 +0000 (UTC) Date: Fri, 1 Sep 2017 12:44:30 -0300 From: Eduardo Habkost To: Markus Armbruster Cc: Eduardo Otubo , mst@redhat.com, qemu-trivial@nongnu.org, Alexander Graf , qemu-devel@nongnu.org, qemu-ppc@nongnu.org, pbonzini@redhat.com, Aurelien Jarno , David Gibson Message-ID: <20170901154430.GN7570@localhost.localdomain> References: <20170901110332.32650-1-otubo@redhat.com> <20170901143016.GK7570@localhost.localdomain> <87lglyzb3p.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87lglyzb3p.fsf@dusky.pond.sub.org> X-Fnord: you can see the fnord User-Agent: Mutt/1.8.3 (2017-05-23) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Fri, 01 Sep 2017 15:44:36 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-trivial] [Qemu-devel] [PATCH] dma/i82374: avoid double creation of i82374 device 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: Fri, 01 Sep 2017 15:44:59 -0000 On Fri, Sep 01, 2017 at 05:34:34PM +0200, Markus Armbruster wrote: > Eduardo Habkost writes: > > > i82374 is compiled in only on ppc and sh4, so I'm CCing the > > maintainers for those architectures. > > > > On Fri, Sep 01, 2017 at 01:03:32PM +0200, Eduardo Otubo wrote: > >> When used with the following command line: > >> > >> ./ppc64-softmmu/qemu-system-ppc64 -S -machine 40p,accel=tcg -device i82374 > >> > >> QEMU with machine type 40p already creates the device i82374. If > >> specified in the command line, it will try to create it again, hence > >> generating the error. > > > > Which error? > > > > > >> One way to avoid this problem is to set > >> user_creatable=false. > >> > >> Signed-off-by: Eduardo Otubo > > > > The patch does more than just avoiding double creation: it > > prevents usage of "-device i82374" completely. > > > > Maybe nobody needs it to work with -device today (would the > > device even work?) and it is OK to set user_creatable=false until > > we fix the crash. But we need to be sure of that. > > > >> --- > >> hw/dma/i82374.c | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/hw/dma/i82374.c b/hw/dma/i82374.c > >> index 6c0f975df0..5275d822e0 100644 > >> --- a/hw/dma/i82374.c > >> +++ b/hw/dma/i82374.c > >> @@ -139,6 +139,7 @@ static void i82374_class_init(ObjectClass *klass, void *data) > >> dc->realize = i82374_realize; > >> dc->vmsd = &vmstate_i82374; > >> dc->props = i82374_properties; > >> + dc->user_creatable = false; > > > > A "Reason:" comment explaining why user_creatable=false is > > mandatory. See the comment above user_creatable declaration in > > qdev-core.h for reference. > > > > I suggest the following: > > > > /* > > * Reason: i82374_realize() crashes (assertion failure inside isa_bus_dma() > > * if the device is instantiated twice. > > */ > > We need to find out *why* it crashes. Once we know, we can likely write > a better comment. It crashes because isa_bus_dma() isn't supposed to be called twice for the same bus. Making isa_bus_dma()/DMA_init()/i82374_realize() return an error instead of asserting would be even better than setting user_creatable=false. -- Eduardo