intel-iommu: set iommu_superpage on VM domains to lowest common denominator

set dmar->iommu_superpage field to the smallest common denominator
of super page sizes supported by all active VT-d engines.  Initialize
this field in intel_iommu_domain_init() API so intel_iommu_map() API
will be able to use iommu_superpage field to determine the appropriate
super page size to use.

Signed-off-by: Allen Kay <allen.m.kay@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 237ef52c8c76..e5883602cb35 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -580,17 +580,18 @@ static void domain_update_iommu_snooping(struct dmar_domain *domain)
 
 static void domain_update_iommu_superpage(struct dmar_domain *domain)
 {
-        int i, mask = 0xf;
+        struct dmar_drhd_unit *drhd;
+        struct intel_iommu *iommu = NULL;
+        int mask = 0xf;
 
         if (!intel_iommu_superpage) {
                 domain->iommu_superpage = 0;
                 return;
         }
 
-        domain->iommu_superpage = 4; /* 1TiB */
-
-        for_each_set_bit(i, &domain->iommu_bmp, g_num_of_iommus) {
-                mask |= cap_super_page_val(g_iommus[i]->cap);
+        /* set iommu_superpage to the smallest common denominator */
+        for_each_active_iommu(iommu, drhd) {
+                mask &= cap_super_page_val(iommu->cap);
                 if (!mask) {
                         break;
                 }
@@ -3748,6 +3749,7 @@ static int intel_iommu_domain_init(struct iommu_domain *domain)
                 vm_domain_exit(dmar_domain);
                 return -ENOMEM;
         }
+        domain_update_iommu_cap(dmar_domain);
         domain->priv = dmar_domain;
 
         return 0;