calculate agaw for each iommu
"SAGAW" capability may be different across iommus. Use a default agaw, but if default agaw is not supported in some iommus, choose a less supported agaw.
Signed-off-by: Weidong Han <weidong.han@intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 9dca689..3ecfa23 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -362,6 +362,28 @@
kmem_cache_free(iommu_iova_cache, iova);
}
+
+static inline int width_to_agaw(int width);
+
+/* calculate agaw for each iommu.
+ * "SAGAW" may be different across iommus, use a default agaw, and
+ * get a supported less agaw for iommus that don't support the default agaw.
+ */
+int iommu_calculate_agaw(struct intel_iommu *iommu)
+{
+ unsigned long sagaw;
+ int agaw = -1;
+
+ sagaw = cap_sagaw(iommu->cap);
+ for (agaw = width_to_agaw(DEFAULT_DOMAIN_ADDRESS_WIDTH);
+ agaw >= 0; agaw--) {
+ if (test_bit(agaw, &sagaw))
+ break;
+ }
+
+ return agaw;
+}
+
/* in native case, each domain is related to only one iommu */
static struct intel_iommu *domain_get_iommu(struct dmar_domain *domain)
{