Re: [Qemu-devel] [PATCH v4 21/21] hw/arm/virt: Add support for Cortex-A57

[Peter Maydell]

On 17 March 2014 07:12, Peter Crosthwaite <address@hidden> wrote:
> On Fri, Mar 7, 2014 at 5:33 AM, Peter Maydell <address@hidden> wrote:
>> Support the Cortex-A57 in the virt machine model.
>>
>> Signed-off-by: Peter Maydell <address@hidden>
>> ---
>> This should perhaps not be just stealing the a15mpcore_priv
>> on the basis that it's a GICv2...
>
> Wont this mean you gets lots of extraneous hardware? Although, with a
> pure virtual machine I guess you can do whatever you really want.

No, a15mpcore_priv only has a GIC in it.

>> ---
>>  hw/arm/virt.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 517f2fe..d985d2e 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -123,6 +123,14 @@ static VirtBoardInfo machines[] = {
>>          .irqmap = a15irqmap,
>>      },
>>      {
>> +        .cpu_model = "cortex-a57",
>> +        /* Use the A15 private peripheral model for now: probably wrong! */
>> +        .qdevname = "a15mpcore_priv",
>
> Can you just change this to gics qdev name? The qdev propnames of gic
> and mpcore ("num-cpu" and "num-irq") should just match. Then perhaps a
> little callback to set gicv2 version property.

That would miss the other thing a15mpcore_priv does for us,
which is to wire up the generic timer outputs from the CPU
objects to the appropriate GIC inputs. (Also the gpio_in
lines on a15mpcore_priv and the gic itself are not the
same: a15mpcore_priv only exposise the SPIs.)

We could in theory write an a57mpcore_priv which was a
carbon copy of a15mpcore_priv, but that seems a bit pointless.
I think it's probably actually reasonable to use a15mpcore_priv
here, with an appropriate comment:

    /* Our A57 has an A15-style GICv2, so we can use a15mpcore_priv */

thanks
-- PMM