----- Original Message ----- > From: "Eduardo Habkost" <ehabk...@redhat.com> > To: "Paolo Bonzini" <pbonz...@redhat.com> > Cc: "Eduardo Otubo" <ot...@redhat.com>, qemu-devel@nongnu.org, > qemu-triv...@nongnu.org, "Michael Tokarev" > <m...@tls.msk.ru>, "Markus Armbruster" <arm...@redhat.com>, "Alexander Graf" > <ag...@suse.de> > Sent: Saturday, September 16, 2017 12:21:13 AM > Subject: Re: [PATCH] dma/i82374: avoid double creation of i82374 device > > On Fri, Sep 15, 2017 at 12:18:11PM +0200, Paolo Bonzini wrote: > > On 15/09/2017 11:06, Eduardo Otubo wrote: > > > QEMU fails when used with the following command line: > > > > > > ./ppc64-softmmu/qemu-system-ppc64 -S -machine 40p,accel=tcg -device > > > i82374 > > > qemu-system-ppc64: hw/isa/isa-bus.c:110: isa_bus_dma: Assertion > > > `!bus->dma[0] && !bus->dma[1]' failed. > > > Aborted (core dumped) > > > > > > The 40p machine type already creates the device i82374. If specified in > > > the > > > command line, it will try to create it again, hence generating the error. > > > The > > > function isa_bus_dma() isn't supposed to be called twice for the same > > > bus. One > > > way to avoid this problem is to set user_creatable=false. > > > > > > A possible fix in a near future would be making > > > isa_bus_dma()/DMA_init()/i82374_realize() return an error instead of > > > asserting > > > as well. > > > > > > Signed-off-by: Eduardo Otubo <ot...@redhat.com> > > > --- > > > hw/dma/i82374.c | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > > > diff --git a/hw/dma/i82374.c b/hw/dma/i82374.c > > > index 6c0f975df0..e76dea8dc7 100644 > > > --- a/hw/dma/i82374.c > > > +++ b/hw/dma/i82374.c > > > @@ -139,6 +139,11 @@ 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; > > > + /* > > > + * Reason: i82374_realize() crashes (assertion failure inside > > > isa_bus_dma() > > > + * if the device is instantiated twice. > > > + */ > > > } > > > > > > static const TypeInfo i82374_info = { > > > > > > > This breaks "make check", doesn't it? > > Why would it? I don't see any test code using -device i82374. > (endianness-test uses -device i82378).
You're right, both Aurelien and I were confused. If you want to accept this patch it would be fine then, even if giving an error may be preferrable. Paolo