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

From: Julien Grall
Date: Wed May 01 2019 - 07:14:48 EST

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.

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?


Julien Grall