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Subject[PATCH 12/13] iommu/vt-d: No need to migrating irq for VT-d Posted-Interrtups
Date
We don't need to migrate the irqs for VT-d Posted-Interrtups here.
When 'pst' is set in IRTE, the associated irq will be posted to
guests instead of interrupt remapping. The destination of the
interrupt is set in Posted-Interrupts Descriptor, and the migration
happens during VCPU scheduling.

Signed-off-by: Feng Wu <feng.wu@intel.com>
---
drivers/iommu/intel_irq_remapping.c | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 87c02fe..249e2b1 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -1038,6 +1038,13 @@ intel_ioapic_set_affinity(struct irq_data *data, const struct cpumask *mask,
if (get_irte(irq, &irte))
return -EBUSY;

+ /*
+ * If the interrupt is for posting, it is used by guests,
+ * we cannot change IRTE here.
+ */
+ if (irte.irq_post_low.pst == 1)
+ return 0;
+
err = assign_irq_vector(irq, cfg, mask);
if (err)
return err;
--
1.7.1


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