Re: [Xen-devel] [PATCH v11 12/34] ARM: vGIC: add LPI VCPU ID to struct pending_irq

[Julien Grall <julien.grall@xxxxxxx>]

Hi Andre,

On 09/06/17 18:41, Andre Przywara wrote:
> The target CPU for an LPI is encoded in the interrupt translation table
> entry, so can't be easily derived from just an LPI number (short of
> walking *all* tables and find the matching LPI).
> To avoid this in case we need to know the VCPU (for the INVALL command,
> for instance), put the VCPU ID in the struct pending_irq, so that it is
> easily accessible.
> We use the remaining 8 bits of padding space for that to avoid enlarging
> the size of struct pending_irq. The number of VCPUs is limited to 127
> at the moment anyway, which we also confirm with a BUILD_BUG_ON.
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxx>

Cheers,

--
Julien Grall

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