Hi,

On 3/19/20 5:16 PM, Marc Zyngier wrote:

Hi Eric,

On 2020-03-19 15:43, Auger Eric wrote:

quoted

Hi Marc,

On 3/19/20 4:21 PM, Marc Zyngier wrote:

quoted

Hi Eric,

[...]

quoted

quoted

quoted

The patch looks good to me but I am now lost about how we retrieve the
pending stat of other hw mapped interrupts. Looks we use
irq->pending_latch always. Is that correct?

Correct. GICv4.0 doesn't give us an architectural way to look at the
vLPI pending state (there isn't even a guarantee about when the GIC
will stop writing to memory, if it ever does).

With GICv4.1, you can introspect the HW state for SGIs. You can also
look at the vLPI state by peeking at the virtual pending table, but
you'd need to unmap the VPE first, which I obviously don't want to do
for this debug interface, specially as it can be used whilst the guest
is up and running.

OK for vLPIs, what about other HW mapped IRQs (arch timer?)

Different kind of HW. With those, the injection is still virtual, so the
SW pending bit is still very much valid. You can actually try and make
the timer interrupt pending, it should show up.

What the irq->hw bit means is "this virtual interrupt is somehow related
to the host_irq". How this is interpreted is completely context-dependent.

OK thank you for refreshing my memories ;-)

Eric

Thanks,

        M.

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