irqchip/gic-v3-mbi: Don't map the MSI page in mbi_compose_m{b, s}i_msg()

The functions mbi_compose_m{b, s}i_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 patch 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 MSI 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@arm.com>
[maz: only call iommu_dma_prepare_msi once, fix commit log accordingly]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/irqchip/irq-gic-v3-mbi.c b/drivers/irqchip/irq-gic-v3-mbi.c
index fbfa7ff6deb1..563a9b366294 100644
--- a/drivers/irqchip/irq-gic-v3-mbi.c
+++ b/drivers/irqchip/irq-gic-v3-mbi.c
@@ -84,6 +84,7 @@ static void mbi_free_msi(struct mbi_range *mbi, unsigned int hwirq,
 static int mbi_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
                                    unsigned int nr_irqs, void *args)
 {
+        msi_alloc_info_t *info = args;
         struct mbi_range *mbi = NULL;
         int hwirq, offset, i, err = 0;
 
@@ -104,6 +105,11 @@ static int mbi_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
 
         hwirq = mbi->spi_start + offset;
 
+        err = iommu_dma_prepare_msi(info->desc,
+                                    mbi_phys_base + GICD_SETSPI_NSR);
+        if (err)
+                return err;
+
         for (i = 0; i < nr_irqs; i++) {
                 err = mbi_irq_gic_domain_alloc(domain, virq + i, hwirq + i);
                 if (err)
@@ -142,7 +148,7 @@ static void mbi_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
         msg[0].address_lo = lower_32_bits(mbi_phys_base + GICD_SETSPI_NSR);
         msg[0].data = data->parent_data->hwirq;
 
-        iommu_dma_map_msi_msg(data->irq, msg);
+        iommu_dma_compose_msi_msg(irq_data_get_msi_desc(data), msg);
 }
 
 #ifdef CONFIG_PCI_MSI
@@ -202,7 +208,7 @@ static void mbi_compose_mbi_msg(struct irq_data *data, struct msi_msg *msg)
         msg[1].address_lo = lower_32_bits(mbi_phys_base + GICD_CLRSPI_NSR);
         msg[1].data = data->parent_data->hwirq;
 
-        iommu_dma_map_msi_msg(data->irq, &msg[1]);
+        iommu_dma_compose_msi_msg(irq_data_get_msi_desc(data), &msg[1]);
 }
 
 /* Platform-MSI specific irqchip */