On Fri, Sep 01, 2017 at 05:34:34PM +0200, Markus Armbruster wrote: > Eduardo Habkost <ehabk...@redhat.com> 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 <ot...@redhat.com> > > > > 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
