Re: [PATCH v2 4/7] irqchip/gic-v3-its: Don't map the MSI page in its_irq_compose_msi_msg()

[Julien Grall]

On 30/04/2019 13:34, Auger Eric wrote:
> Hi Julien,

Hi Eric,

Thank you for the review!

> On 4/29/19 4:44 PM, Julien Grall wrote:
> > its_irq_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 GICv3 ITS driver is reworked to avoid executing preemptible code in
> > non-preemptible context. This can be achieved by preparing the MSI
> > maping when allocating the MSI interrupt.
> mapping
> > Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> >
> > ---
> >      Changes in v2:
> >          - Rework the commit message to use imperative mood
> > ---
> >   drivers/irqchip/irq-gic-v3-its.c | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> > index 7577755bdcf4..12ddbcfe1b1e 100644
> > --- a/drivers/irqchip/irq-gic-v3-its.c
> > +++ b/drivers/irqchip/irq-gic-v3-its.c
> > @@ -1179,7 +1179,7 @@ static void its_irq_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
> >   	msg->address_hi		= upper_32_bits(addr);
> >   	msg->data		= its_get_event_id(d);
> >   
> > -	iommu_dma_map_msi_msg(d->irq, msg);
> > +	iommu_dma_compose_msi_msg(irq_data_get_msi_desc(d), msg);
> >   }
> >   
> >   static int its_irq_set_irqchip_state(struct irq_data *d,
> > @@ -2566,6 +2566,7 @@ static int its_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> >   {
> >   	msi_alloc_info_t *info = args;
> >   	struct its_device *its_dev = info->scratchpad[0].ptr;
> > +	struct its_node *its = its_dev->its;
> >   	irq_hw_number_t hwirq;
> >   	int err;
> >   	int i;
> > @@ -2574,6 +2575,8 @@ static int its_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> >   	if (err)
> >   		return err;
> >   
> > +	err = iommu_dma_prepare_msi(info->desc, its->get_msi_base(its_dev));
> Test err as in gicv2m driver?

Hmmm yes. Marc, do you want me to respin the patch?

Cheers,

--
Julien Grall