From: Liu Yi L <yi.l....@intel.com>

[ Upstream commit 423d39d8518c1bba12e0889a92beeddbb1502392 ]

The helper functions should not modify the pasid entries which are still
in use. Add a check against present bit.

Signed-off-by: Liu Yi L <yi.l....@intel.com>
Link: https://lore.kernel.org/r/20210817042425.1784279-1-yi.l....@intel.com
Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
Link: 
https://lore.kernel.org/r/20210818134852.1847070-10-baolu...@linux.intel.com
Signed-off-by: Joerg Roedel <jroe...@suse.de>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/iommu/intel/pasid.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 581c694b7cf4..a4e79d52be27 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -540,6 +540,10 @@ void intel_pasid_tear_down_entry(struct intel_iommu 
*iommu, struct device *dev,
                devtlb_invalidation_with_pasid(iommu, dev, pasid);
 }
 
+/*
+ * This function flushes cache for a newly setup pasid table entry.
+ * Caller of it should not modify the in-use pasid table entries.
+ */
 static void pasid_flush_caches(struct intel_iommu *iommu,
                                struct pasid_entry *pte,
                               u32 pasid, u16 did)
@@ -591,6 +595,10 @@ int intel_pasid_setup_first_level(struct intel_iommu 
*iommu,
        if (WARN_ON(!pte))
                return -EINVAL;
 
+       /* Caller must ensure PASID entry is not in use. */
+       if (pasid_pte_is_present(pte))
+               return -EBUSY;
+
        pasid_clear_entry(pte);
 
        /* Setup the first level page table pointer: */
@@ -690,6 +698,10 @@ int intel_pasid_setup_second_level(struct intel_iommu 
*iommu,
                return -ENODEV;
        }
 
+       /* Caller must ensure PASID entry is not in use. */
+       if (pasid_pte_is_present(pte))
+               return -EBUSY;
+
        pasid_clear_entry(pte);
        pasid_set_domain_id(pte, did);
        pasid_set_slptr(pte, pgd_val);
@@ -729,6 +741,10 @@ int intel_pasid_setup_pass_through(struct intel_iommu 
*iommu,
                return -ENODEV;
        }
 
+       /* Caller must ensure PASID entry is not in use. */
+       if (pasid_pte_is_present(pte))
+               return -EBUSY;
+
        pasid_clear_entry(pte);
        pasid_set_domain_id(pte, did);
        pasid_set_address_width(pte, iommu->agaw);
-- 
2.30.2

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