[RFC PATCH v2 06/10] iommu/vt-d: Return ID associated with an auxiliary domain

[Lu Baolu <baolu.lu@linux.intel.com>]

This adds support to return the default pasid associated with
an auxiliary domain. The PCI device which is bound with this
domain should use this value as the pasid for all DMA requests
of the subset of device which is isolated and protected with
this domain.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 784bd496f316..1ba39f120a38 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5544,6 +5544,14 @@ static void intel_iommu_disable_auxd(struct device *dev)
 	spin_unlock_irqrestore(&device_domain_lock, flags);
 }
 
+static int intel_iommu_auxd_id(struct iommu_domain *domain)
+{
+	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+
+	return dmar_domain->default_pasid > 0 ?
+			dmar_domain->default_pasid : -EINVAL;
+}
+
 const struct iommu_ops intel_iommu_ops = {
 	.capable		= intel_iommu_capable,
 	.domain_alloc		= intel_iommu_domain_alloc,
@@ -5560,6 +5568,7 @@ const struct iommu_ops intel_iommu_ops = {
 	.device_group		= pci_device_group,
 	.enable_auxd		= intel_iommu_enable_auxd,
 	.disable_auxd		= intel_iommu_disable_auxd,
+	.auxd_id		= intel_iommu_auxd_id,
 	.pgsize_bitmap		= INTEL_IOMMU_PGSIZES,
 };
 
-- 
2.17.1