Re: [Qemu-devel] [Qemu-trivial] [PATCH] dma/i82374: avoid double creation of i82374 device

[Eduardo Otubo <otubo@redhat.com>]

(oups, forgot the v2 on Subject)

On Fri, Sep 15, 2017 at 11:06:43AM +0200, 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 <otubo@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 = {
> -- 
> 2.13.5
> 
> 

-- 
Eduardo Otubo
Senior Software Engineer @ RedHat