[PATCH RFC 12/13] iommu/vt-d: Add a helper to retrieve PID address

[Jacob Pan <jacob.jun.pan@linux.intel.com>]

From: Thomas Gleixner <tglx@linutronix.de>

When programming IRTE for posted mode, we need to retrieve the physical
address of the posted interrupt descriptor (PID) that belongs to it's
target CPU.

This per CPU PID has already been set up during cpu_init().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
 drivers/iommu/intel/irq_remapping.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c
index f2870d3c8313..971e6c37002f 100644
--- a/drivers/iommu/intel/irq_remapping.c
+++ b/drivers/iommu/intel/irq_remapping.c
@@ -1125,6 +1125,15 @@ struct irq_remap_ops intel_irq_remap_ops = {
 	.reenable		= reenable_irq_remapping,
 	.enable_faulting	= enable_drhd_fault_handling,
 };
+#ifdef CONFIG_X86_POSTED_MSI
+
+static u64 get_pi_desc_addr(struct irq_data *irqd)
+{
+	int cpu = cpumask_first(irq_data_get_effective_affinity_mask(irqd));
+
+	return __pa(per_cpu_ptr(&posted_interrupt_desc, cpu));
+}
+#endif
 
 static void intel_ir_reconfigure_irte(struct irq_data *irqd, bool force)
 {
-- 
2.25.1