Re: [PATCH v4 07/17] xen/arm: ITS: Add virtual ITS commands support

[Vijay Kilari <vijay.kilari@gmail.com>]

On Mon, Jul 13, 2015 at 2:52 PM, Ian Campbell <ian.campbell@citrix.com> wrote:
> On Sat, 2015-07-11 at 20:19 +0530, Vijay Kilari wrote:
>> >> +int vgic_its_process_cmd(struct vcpu *v, struct vgic_its *vits)
>> >> +{
>> >> +    its_cmd_block virt_cmd;
>> >> +
>> >> +    ASSERT(spin_is_locked(&vits->lock));
>> >> +
>> >> +    do {
>> >> +        if ( vgic_its_read_virt_cmd(v, vits, &virt_cmd) )
>> >> +            goto err;
>> >> +        if ( vgic_its_parse_its_command(v, vits, &virt_cmd) )
>> >> +            goto err;
>> >> +        vgic_its_update_read_ptr(v, vits);
>> >> +    } while ( vits->cmd_write != vits->cmd_write_save );
>> >
>> > I can't find anywhere other than here where vits->cmd_write is touched.
>> > What am I missing?
>>
>>    It is written by guest by GITS_CWRITER emulation in patch #9
>
> Ah, then please reverse the order so that the variable comes first and
> the target comes second.
>
> Also I think you need to find a better name that "cmd_write_save".
> Something which indicates the progress made perhaps? But why isn't this
> just cmd_read? Why the separate progress pointer?

I will check If I can use cmd_read.

BTW, I want to know if atomic_t supports 64-bit access?.
I have not made cmd_read as atomic_t.