linux-kernel - [PATCH 1/1] iommu/vt-d: Tweak the description of a DMA fault

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Date:   Wed, 12 May 2021 14:50:12 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>
Cc:     ashok.raj@...el.com, kevin.tian@...el.com, jacob.jun.pan@...el.com,
        yi.l.liu@...el.com, sanjay.k.kumar@...el.com,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH 1/1] iommu/vt-d: Tweak the description of a DMA fault

The Intel IOMMU driver reports the DMA fault reason in a decimal number
while the VT-d specification uses a hexadecimal one. It's inconvenient
that users need to covert them everytime before consulting the spec.
Let's use hexadecimal number for a DMA fault reason.

The fault message uses 0xffffffff as PASID for DMA requests w/o PASID.
This is confusing. Tweak this by adding "w/o PASID" explicitly.

Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/intel/dmar.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 1757ac1e1623..11e37d2c2af2 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -1911,15 +1911,21 @@ static int dmar_fault_do_one(struct intel_iommu *iommu, int type,
 	reason = dmar_get_fault_reason(fault_reason, &fault_type);
 
 	if (fault_type == INTR_REMAP)
-		pr_err("[INTR-REMAP] Request device [%02x:%02x.%d] fault index %llx [fault reason %02d] %s\n",
-			source_id >> 8, PCI_SLOT(source_id & 0xFF),
-			PCI_FUNC(source_id & 0xFF), addr >> 48,
-			fault_reason, reason);
-	else
-		pr_err("[%s] Request device [%02x:%02x.%d] PASID %x fault addr %llx [fault reason %02d] %s\n",
+		pr_err("[INTR-REMAP] Request device [%02x:%02x.%d] fault index %llx [fault reason %02xh] %s\n",
+		       source_id >> 8, PCI_SLOT(source_id & 0xFF),
+		       PCI_FUNC(source_id & 0xFF), addr >> 48,
+		       fault_reason, reason);
+	else if (pasid == INVALID_IOASID)
+		pr_err("[%s w/o PASID] Request device [%02x:%02x.%d] fault addr %llx [fault reason %02xh] %s\n",
 		       type ? "DMA Read" : "DMA Write",
 		       source_id >> 8, PCI_SLOT(source_id & 0xFF),
-		       PCI_FUNC(source_id & 0xFF), pasid, addr,
+		       PCI_FUNC(source_id & 0xFF), addr,
+		       fault_reason, reason);
+	else
+		pr_err("[%s w/ PASID %x] Request device [%02x:%02x.%d] fault addr %llx [fault reason %02xh] %s\n",
+		       type ? "DMA Read" : "DMA Write", pasid,
+		       source_id >> 8, PCI_SLOT(source_id & 0xFF),
+		       PCI_FUNC(source_id & 0xFF), addr,
 		       fault_reason, reason);
 	return 0;
 }
@@ -1987,7 +1993,7 @@ irqreturn_t dmar_fault(int irq, void *dev_id)
 		if (!ratelimited)
 			/* Using pasid -1 if pasid is not present */
 			dmar_fault_do_one(iommu, type, fault_reason,
-					  pasid_present ? pasid : -1,
+					  pasid_present ? pasid : INVALID_IOASID,
 					  source_id, guest_addr);
 
 		fault_index++;
-- 
2.25.1