From a919a018cccf999aa56d7f9adeae0525b01b7434 Mon Sep 17 00:00:00 2001
From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Date: Wed, 5 Mar 2014 18:54:18 -0600
Subject: iommu/amd: Fix logic to determine and checking max PASID
In reality, the spec can only support 16-bit PASID since
INVALIDATE_IOTLB_PAGES and COMPLETE_PPR_REQUEST commands only allow 16-bit
PASID. So, we updated the PASID_MASK accordingly and invoke BUG_ON
if the hardware is reporting PASmax more than 16-bit.
Besides, max PASID is defined as ((2^(PASmax+1)) - 1). The current does not
determine this correctly.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: Jay Cornwall <Jay.Cornwall@amd.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>
---
drivers/iommu/amd_iommu_init.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
(limited to 'drivers/iommu/amd_iommu_init.c')
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 28b4bea7c109..b76c58dbe30c 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -150,7 +150,7 @@ int amd_iommus_present;
bool amd_iommu_np_cache __read_mostly;
bool amd_iommu_iotlb_sup __read_mostly = true;
-u32 amd_iommu_max_pasids __read_mostly = ~0;
+u32 amd_iommu_max_pasid __read_mostly = ~0;
bool amd_iommu_v2_present __read_mostly;
bool amd_iommu_pc_present __read_mostly;
@@ -1231,14 +1231,16 @@ static int iommu_init_pci(struct amd_iommu *iommu)
if (iommu_feature(iommu, FEATURE_GT)) {
int glxval;
- u32 pasids;
- u64 shift;
+ u32 max_pasid;
+ u64 pasmax;
- shift = iommu->features & FEATURE_PASID_MASK;
- shift >>= FEATURE_PASID_SHIFT;
- pasids = (1 << shift);
+ pasmax = iommu->features & FEATURE_PASID_MASK;
+ pasmax >>= FEATURE_PASID_SHIFT;
+ max_pasid = (1 << (pasmax + 1)) - 1;
- amd_iommu_max_pasids = min(amd_iommu_max_pasids, pasids);
+ amd_iommu_max_pasid = min(amd_iommu_max_pasid, max_pasid);
+
+ BUG_ON(amd_iommu_max_pasid & ~PASID_MASK);
glxval = iommu->features & FEATURE_GLXVAL_MASK;
glxval >>= FEATURE_GLXVAL_SHIFT;
--
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