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From:   Lu Baolu <baolu.lu@linux.intel.com>
To:     Joerg Roedel <joro@8bytes.org>
Cc:     YueHaibing <yuehaibing@huawei.com>,
        Yanfei Xu <yanfei.xu@intel.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>,
        iommu@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: [PATCH 06/13] iommu/vt-d: Prepare for set_dev_pasid callback
Date:   Wed,  9 Aug 2023 20:47:59 +0800
Message-Id: <20230809124806.45516-7-baolu.lu@linux.intel.com>
In-Reply-To: <20230809124806.45516-1-baolu.lu@linux.intel.com>
References: <20230809124806.45516-1-baolu.lu@linux.intel.com>
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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the introduction of the set_dev_pasid callback, this assumption is no
longer valid.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>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20230802212427.1497170-7-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);
 }
 
-- 
2.34.1