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SubjectRe: [PATCH] irqchip/gic-v3-its: Flush GICR caching for a cross node collection move of an irq
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On 20/12/17 09:15, Ganapatrao Kulkarni wrote:
> When an interrupt is moved, it is possible that an implementation that
> supports caching might still have cached data for a previous
> (no longer valid) mapping of the interrupt. In particular, in a distributed
> GIC implementation like multi-socket SoC platfroms. Hence it is necessary
> to flush cached entries after cross node collection migration.
>
> Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
> ---
> drivers/irqchip/irq-gic-v3-its.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 4039e64..ea849a1 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -1119,6 +1119,12 @@ static int its_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
> if (cpu != its_dev->event_map.col_map[id]) {
> target_col = &its_dev->its->collections[cpu];
> its_send_movi(its_dev, target_col, id);
> + /* Issue INV for cross node collection move on
> + * multi socket systems.
> + */
> + if (cpu_to_node(cpu) !=
> + cpu_to_node(its_dev->event_map.col_map[id]))
> + its_send_inv(its_dev, id);
> its_dev->event_map.col_map[id] = cpu;
> irq_data_update_effective_affinity(d, cpumask_of(cpu));
> }
>

The MOVI command doesn't have any such requirement (it only mandates
synchronization), and doesn't say anything about distributed vs monolithic.

What am I missing?

M.
--
Jazz is not dead. It just smells funny...

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