Hi Julien,
On 4/29/19 4:44 PM, Julien Grall wrote:
> gicv2m_compose_msi_msg() may be called from non-preemptible context.
> However, on RT, iommu_dma_map_msi_msg() requires to be called from a
> preemptible context.
>
> A recent change split iommu_dma_map_msi_msg() in two new functions:
> one that should be called in preemptible context, the other does
> not have any requirement.
>
> The GICv2m driver is reworked to avoid executing preemptible code in
> non-preemptible context. This can be achieved by preparing the MSI
> mapping when allocating the MSI interrupt.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Thanks
Eric
>
> ---
> Changes in v2:
> - Rework the commit message to use imperative mood
> ---
> drivers/irqchip/irq-gic-v2m.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
> index f5fe0100f9ff..4359f0583377 100644
> --- a/drivers/irqchip/irq-gic-v2m.c
> +++ b/drivers/irqchip/irq-gic-v2m.c
> @@ -110,7 +110,7 @@ static void gicv2m_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
> if (v2m->flags & GICV2M_NEEDS_SPI_OFFSET)
> msg->data -= v2m->spi_offset;
>
> - iommu_dma_map_msi_msg(data->irq, msg);
> + iommu_dma_compose_msi_msg(irq_data_get_msi_desc(data), msg);
> }
>
> static struct irq_chip gicv2m_irq_chip = {
> @@ -167,6 +167,7 @@ static void gicv2m_unalloc_msi(struct v2m_data *v2m, unsigned int hwirq,
> static int gicv2m_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> unsigned int nr_irqs, void *args)
> {
> + msi_alloc_info_t *info = args;
> struct v2m_data *v2m = NULL, *tmp;
> int hwirq, offset, i, err = 0;
>
> @@ -186,6 +187,11 @@ static int gicv2m_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
>
> hwirq = v2m->spi_start + offset;
>
> + err = iommu_dma_prepare_msi(info->desc,
> + v2m->res.start + V2M_MSI_SETSPI_NS);
> + if (err)
> + return err;
> +
> for (i = 0; i < nr_irqs; i++) {
> err = gicv2m_irq_gic_domain_alloc(domain, virq + i, hwirq + i);
> if (err)
>
