On 03/21/2013 06:51:57 AM, Alexander Graf wrote:
On 21.03.2013, at 12:49, Alexander Graf wrote:
>
> On 21.03.2013, at 12:44, Peter Maydell wrote:
>
>> On 21 March 2013 11:38, Alexander Graf <ag...@suse.de> wrote:
>>>
>>> On 21.03.2013, at 12:32, Peter Maydell wrote:
>>>
>>>> On 21 March 2013 11:29, Alexander Graf <ag...@suse.de> wrote:
>>>>> On 21.03.2013, at 12:22, Peter Maydell wrote:
>>>>>> We already nest the VGIC inside another memory region (the
a15mpcore
>>>>>> container), and it works fine. This function is just iterating
through
>>>>>> "everything any device asked me to tell the kernel about".
>>>>>
>>>>> So kda is the real physical offset? I'm having a hard time
reading that code :). According to this function:
>>>>>
>>>>> static void kvm_arm_devlistener_add(MemoryListener *listener,
>>>>> MemoryRegionSection *section)
>>>>> {
>>>>> KVMDevice *kd;
>>>>>
>>>>> QSLIST_FOREACH(kd, &kvm_devices_head, entries) {
>>>>> if (section->mr == kd->mr) {
>>>>> kd->kda.addr = section->offset_within_address_space;
>>>>> }
>>>>> }
>>>>> }
What if the update is to a parent memory region, not to the one
directly associated with the device?
Or does add() get called for all child regions (recursively) in such
cases?
>>> The distinction on whether a region is handled by KVM really needs
>>> to be done by the device model.
>>
>> It is -- the device model is what calls kvm_arm_register_device().
>> It's just the mechanics of "how do we tell the kernel the right
>> address for this region at the point when we know it" that are
>> handled in kvm.c.
>
> I think I'm slowly grasping what you're aiming at :). Ok, that
works. You do actually do the listener in the device model, just that
you pass code responsibility over to kvm.c.
>
> That's perfectly valid and sounds like a good model that Scott
probably wants to follow as well :).
s/follow/evaluate/ :).
The currently proposed device api doesn't have a generic notion of
device regions. Regions are a per-device property, because a single
device can have multiple regions.
However, maybe with a bit of brainstorming we could come up with a
reasonably generic scheme.
In the kernel API? Or do you mean a generic scheme within QEMU that
encodes any reasonably expected mechanism for setting the device adress
(e.g. assume that it is either a 64-bit attribute, or uses the legacy
ARM API), or perhaps a callback into device code?
The MPIC's memory listener isn't that much code... I'm not sure there's
a great need for a central KVM registry.
-Scott
