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From:   Jacob Pan <jacob.jun.pan@linux.intel.com>
To:     LKML <linux-kernel@vger.kernel.org>, iommu@lists.linux.dev,
        "Lu Baolu" <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>,
        "Robin Murphy" <robin.murphy@arm.com>
Cc:     Jason Gunthorpe <jgg@nvidia.com>, "Will Deacon" <will@kernel.org>,
        "Tian, Kevin" <kevin.tian@intel.com>, Yi Liu <yi.l.liu@intel.com>,
        "Yu, Fenghua" <fenghua.yu@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>
Subject: [PATCH v11 6/8] iommu/vt-d: Prepare for set_dev_pasid callback
Date:   Mon, 24 Jul 2023 15:25:36 -0700
Message-Id: <20230724222538.3902553-7-jacob.jun.pan@linux.intel.com>
In-Reply-To: <20230724222538.3902553-1-jacob.jun.pan@linux.intel.com>
References: <20230724222538.3902553-1-jacob.jun.pan@linux.intel.com>
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From: Lu Baolu <baolu.lu@linux.intel.com>

The domain_flush_pasid_iotlb() helper function is used to flush the IOTLB
entries for a given PASID. Previously, this function assumed that
RID2PASID was only used for the first-level DMA translation. However, with
the introduction of the set_dev_pasid callback, this assumption is no
longer valid.

Add a check before using the RID2PASID for PASID invalidation. This check
ensures that the domain has been attached to a physical device before
using RID2PASID.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index bdde38a5e43a..4a41aca6a2ba 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1475,7 +1475,8 @@ static void domain_flush_pasid_iotlb(struct intel_iommu *iommu,
 	unsigned long flags;
 
 	spin_lock_irqsave(&domain->lock, flags);
-	qi_flush_piotlb(iommu, did, IOMMU_NO_PASID, addr, npages, ih);
+	if (!list_empty(&domain->devices))
+		qi_flush_piotlb(iommu, did, IOMMU_NO_PASID, addr, npages, ih);
 	spin_unlock_irqrestore(&domain->lock, flags);
 }
 
-- 
2.25.1