Received: from eggs.gnu.org ([2001:4830:134:3::10]:50293) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dnny3-0003W2-FG for qemu-devel@nongnu.org; Fri, 01 Sep 2017 11:34:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dnny0-0007tg-Ix for qemu-devel@nongnu.org; Fri, 01 Sep 2017 11:34:47 -0400 From: Markus Armbruster References: <20170901110332.32650-1-otubo@redhat.com> <20170901143016.GK7570@localhost.localdomain> Date: Fri, 01 Sep 2017 17:34:34 +0200 In-Reply-To: <20170901143016.GK7570@localhost.localdomain> (Eduardo Habkost's message of "Fri, 1 Sep 2017 11:30:16 -0300") Message-ID: <87lglyzb3p.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH] dma/i82374: avoid double creation of i82374 device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost 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 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.