Commit 8208d170 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

irqchip/gic-v3-its: Align PCI Multi-MSI allocation on their size

The way we allocate events works fine in most cases, except
when multiple PCI devices share an ITS-visible DevID, and that
one of them is trying to use MultiMSI allocation.

In that case, our allocation is not guaranteed to be zero-based
anymore, and we have to make sure we allocate it on a boundary
that is compatible with the PCI Multi-MSI constraints.

Fix this by allocating the full region upfront instead of iterating
over the number of MSIs. MSI-X are always allocated one by one,
so this shouldn't change anything on that front.

Fixes: b48ac83d

 ("irqchip: GICv3: ITS: MSI support")
Reported-by: default avatarArd Biesheuvel <>
Tested-by: default avatarArd Biesheuvel <>
Signed-off-by: default avatarMarc Zyngier <>
parent 8fa4e55b
......@@ -2399,13 +2399,14 @@ static void its_free_device(struct its_device *its_dev)
static int its_alloc_device_irq(struct its_device *dev, irq_hw_number_t *hwirq)
static int its_alloc_device_irq(struct its_device *dev, int nvecs, irq_hw_number_t *hwirq)
int idx;
idx = find_first_zero_bit(dev->event_map.lpi_map,
if (idx == dev->event_map.nr_lpis)
idx = bitmap_find_free_region(dev->event_map.lpi_map,
if (idx < 0)
return -ENOSPC;
*hwirq = dev->event_map.lpi_base + idx;
......@@ -2501,21 +2502,21 @@ static int its_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
int err;
int i;
for (i = 0; i < nr_irqs; i++) {
err = its_alloc_device_irq(its_dev, &hwirq);
if (err)
return err;
err = its_alloc_device_irq(its_dev, nr_irqs, &hwirq);
if (err)
return err;
err = its_irq_gic_domain_alloc(domain, virq + i, hwirq);
for (i = 0; i < nr_irqs; i++) {
err = its_irq_gic_domain_alloc(domain, virq + i, hwirq + i);
if (err)
return err;
irq_domain_set_hwirq_and_chip(domain, virq + i,
hwirq, &its_irq_chip, its_dev);
hwirq + i, &its_irq_chip, its_dev);
irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(virq + i)));
pr_debug("ID:%d pID:%d vID:%d\n",
(int)(hwirq - its_dev->event_map.lpi_base),
(int) hwirq, virq + i);
(int)(hwirq + i - its_dev->event_map.lpi_base),
(int)(hwirq + i), virq + i);
return 0;
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