[lkml]   [2020]   [Dec]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC PATCH v1 3/4] KVM: arm64: GICv4.1: Restore VLPI's pending state to physical side
On 2020/12/1 19:50, Marc Zyngier wrote:
> On 2020-12-01 11:40, Shenming Lu wrote:
>> On 2020/12/1 18:55, Marc Zyngier wrote:
>>> On 2020-11-30 07:23, Shenming Lu wrote:
>>> Hi Shenming,
>>>> We are pondering over this problem these days, but still don't get a
>>>> good solution...
>>>> Could you give us some advice on this?
>>>> Or could we move the restoring of the pending states (include the sync
>>>> from guest RAM and the transfer to HW) to the GIC VM state change handler,
>>>> which is completely corresponding to save_pending_tables (more symmetric?)
>>>> and don't expose GICv4...
>>> What is "the GIC VM state change handler"? Is that a QEMU thing?
>> Yeah, it is a a QEMU thing...
>>> We don't really have that concept in KVM, so I'd appreciate if you could
>>> be a bit more explicit on this.
>> My thought is to add a new interface (to QEMU) for the restoring of
>> the pending states, which is completely corresponding to
>> And it is called from the GIC VM state change handler in QEMU, which
>> is happening after the restoring (call kvm_vgic_v4_set_forwarding())
>> but before the starting (running) of the VFIO device.
> Right, that makes sense. I still wonder how much the GIC save/restore
> stuff differs from other architectures that implement similar features,
> such as x86 with VT-D.

I am not familiar with it...

> It is obviously too late to change the userspace interface, but I wonder
> whether we missed something at the time.

The interface seems to be really asymmetrical?...

Or is there a possibility that we could know which irq is hw before the VFIO
device calls kvm_vgic_v4_set_forwarding()?


> Thanks,
>         M.

 \ /
  Last update: 2020-12-01 13:18    [W:0.104 / U:1.744 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site