Re: [Qemu-devel] [PATCH for-1.6] mips_malta: do not raise exceptions when accessing invalid memory

[James Hogan]

On 12 August 2013 20:44, Aurelien Jarno <address@hidden> wrote:
> Since commit c658b94f6e8c206c59d02aa6fbac285b86b53d2c, MIPS raises
> exceptions when accessing invalid memory. This is not the correct
> behaviour for MIPS Malta Core LV, as the GT-64120A system controller
> just ignore undecoded access. This feature is used by the Linux kernel
> to probe for some devices.
>
> Emulate the correct behaviour in QEMU by adding an empty slot covering
> the entire memory space decoded by the GT-64120A.
>
> Signed-off-by: Aurelien Jarno <address@hidden>
> ---

<snip>

> @@ -908,6 +909,11 @@ void mips_malta_init(QEMUMachineInitArgs *args)
>      DeviceState *dev = qdev_create(NULL, TYPE_MIPS_MALTA);
>      MaltaState *s = MIPS_MALTA(dev);
>
> +    /* The whole address space decoded by the GT-64120A doesn't generate
> +       exception when accessing invalid memory. Create an empty slot to
> +       emulate this feature. */
> +    empty_slot_init(0, 0x1fffffff);

Out of interest, any particular reason not to put this in
hw/mips/gt64xxx_pci.c? As far as I can tell from your description it's
specific to the GT-64* system controller rather than the malta board?

Cheers
James