[PATCH v2 15/16] iommu/amd: Initialize iommu_device->max_pasids

[Vasant Hegde <vasant.hegde@amd.com>]

Commit 1adf3cc20d69 ("iommu: Add max_pasids field in struct iommu_device")
introduced a variable struct iommu_device.max_pasids to track max
PASIDS supported by each IOMMU.

Let us initialize this field for AMD IOMMU. IOMMU core will use this value
to set max PASIDs per device (see __iommu_probe_device()).

Also remove unused global 'amd_iommu_max_pasid' variable.

Finally current code restricts max PASIDs to 16 bits and calls BUG_ON if
max PASID is more than 16bit. This patch replaces BUG_ON with WARN_ON
as system can continue to work with 16-bit PASID.

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
---
 drivers/iommu/amd/amd_iommu_types.h |  3 ---
 drivers/iommu/amd/init.c            | 10 +++-------
 2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index 445b58c24d20..4c80075c0454 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -895,9 +895,6 @@ extern unsigned amd_iommu_aperture_order;
 /* allocation bitmap for domain ids */
 extern unsigned long *amd_iommu_pd_alloc_bitmap;
 
-/* Smallest max PASID supported by any IOMMU in the system */
-extern u32 amd_iommu_max_pasid;
-
 extern bool amd_iommu_force_isolation;
 
 /* Max levels of glxval supported */
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 1f56478ae74e..6441c81467ab 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -185,8 +185,6 @@ static int amd_iommus_present;
 bool amd_iommu_np_cache __read_mostly;
 bool amd_iommu_iotlb_sup __read_mostly = true;
 
-u32 amd_iommu_max_pasid __read_mostly = ~0;
-
 static bool amd_iommu_pc_present __read_mostly;
 bool amdr_ivrs_remap_support __read_mostly;
 
@@ -2086,16 +2084,14 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
 
 	if (iommu_feature(iommu, FEATURE_GT)) {
 		int glxval;
-		u32 max_pasid;
 		u64 pasmax;
 
 		pasmax = iommu->features & FEATURE_PASID_MASK;
 		pasmax >>= FEATURE_PASID_SHIFT;
-		max_pasid  = (1 << (pasmax + 1)) - 1;
-
-		amd_iommu_max_pasid = min(amd_iommu_max_pasid, max_pasid);
+		iommu->iommu.max_pasids = (1 << (pasmax + 1)) - 1;
 
-		BUG_ON(amd_iommu_max_pasid & ~PASID_MASK);
+		WARN_ON(iommu->iommu.max_pasids & ~PASID_MASK);
+		iommu->iommu.max_pasids &= PASID_MASK;
 
 		glxval   = iommu->features & FEATURE_GLXVAL_MASK;
 		glxval >>= FEATURE_GLXVAL_SHIFT;
-- 
2.31.1