[RFC PATCH v2 02/10] iommu/vt-d: Add multiple domains per device query

[Lu Baolu]

Add the response to IOMMU_CAP_AUX_DOMAIN capability query
through iommu_capable(). Return true if IOMMUs support the
scalable mode, return false otherwise.

Cc: Ashok Raj <ashok....@intel.com>
Cc: Jacob Pan <jacob.jun....@linux.intel.com>
Cc: Kevin Tian <kevin.t...@intel.com>
Cc: Liu Yi L <yi.l....@intel.com>
Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 3e49d4029058..891ae70e7bf2 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5193,12 +5193,39 @@ static phys_addr_t intel_iommu_iova_to_phys(struct 
iommu_domain *domain,
        return phys;
 }
 
+static inline bool scalable_mode_support(void)
+{
+       struct dmar_drhd_unit *drhd;
+       struct intel_iommu *iommu;
+       bool ret = true;
+
+       rcu_read_lock();
+       for_each_active_iommu(iommu, drhd) {
+               if (!sm_supported(iommu)) {
+                       ret = false;
+                       break;
+               }
+       }
+       rcu_read_unlock();
+
+       return ret;
+}
+
 static bool intel_iommu_capable(enum iommu_cap cap)
 {
-       if (cap == IOMMU_CAP_CACHE_COHERENCY)
+       switch (cap) {
+       case IOMMU_CAP_CACHE_COHERENCY:
                return domain_update_iommu_snooping(NULL) == 1;
-       if (cap == IOMMU_CAP_INTR_REMAP)
+       case IOMMU_CAP_INTR_REMAP:
                return irq_remapping_enabled == 1;
+       case IOMMU_CAP_AUX_DOMAIN:
+               return scalable_mode_support();
+       case IOMMU_CAP_NOEXEC:
+       /* PASSTHROUGH */
+       default:
+               pr_info("Unsupported capability query %d\n", cap);
+               break;
+       }
 
        return false;
 }
-- 
2.17.1

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