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From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: kevin.tian@intel.com, ashok.raj@intel.com,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	jacob.jun.pan@intel.com
Subject: [PATCH 1/1] iommu/vt-d: Remove unnecessary WARN_ON_ONCE()
Date: Thu, 16 Jan 2020 09:52:36 +0800	[thread overview]
Message-ID: <20200116015236.4458-1-baolu.lu@linux.intel.com> (raw)

Address field in device TLB invalidation descriptor is qualified
by the S field. If S field is zero, a single page at page address
specified by address [63:12] is requested to be invalidated. If S
field is set, the least significant bit in the address field with
value 0b (say bit N) indicates the invalidation address range. The
spec doesn't require the address [N - 1, 0] to be cleared, hence
remove the unnecessary WARN_ON_ONCE().

Otherwise, the caller might set "mask = MAX_AGAW_PFN_WIDTH" in order
to invalidating all the cached mappings on an endpoint, and below
overflow error will be triggered.

[...]
UBSAN: Undefined behaviour in drivers/iommu/dmar.c:1354:3
shift exponent 64 is too large for 64-bit type 'long long unsigned int'
[...]

Reported-and-tested-by: Frank <fgndev@posteo.de>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/dmar.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 613b7153905d..071bb42bbbc5 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1354,7 +1354,6 @@ void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
 	struct qi_desc desc;
 
 	if (mask) {
-		WARN_ON_ONCE(addr & ((1ULL << (VTD_PAGE_SHIFT + mask)) - 1));
 		addr |= (1ULL << (VTD_PAGE_SHIFT + mask - 1)) - 1;
 		desc.qw1 = QI_DEV_IOTLB_ADDR(addr) | QI_DEV_IOTLB_SIZE;
 	} else
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: ashok.raj@intel.com, jacob.jun.pan@intel.com,
	kevin.tian@intel.com, iommu@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, Lu Baolu <baolu.lu@linux.intel.com>
Subject: [PATCH 1/1] iommu/vt-d: Remove unnecessary WARN_ON_ONCE()
Date: Thu, 16 Jan 2020 09:52:36 +0800	[thread overview]
Message-ID: <20200116015236.4458-1-baolu.lu@linux.intel.com> (raw)

Address field in device TLB invalidation descriptor is qualified
by the S field. If S field is zero, a single page at page address
specified by address [63:12] is requested to be invalidated. If S
field is set, the least significant bit in the address field with
value 0b (say bit N) indicates the invalidation address range. The
spec doesn't require the address [N - 1, 0] to be cleared, hence
remove the unnecessary WARN_ON_ONCE().

Otherwise, the caller might set "mask = MAX_AGAW_PFN_WIDTH" in order
to invalidating all the cached mappings on an endpoint, and below
overflow error will be triggered.

[...]
UBSAN: Undefined behaviour in drivers/iommu/dmar.c:1354:3
shift exponent 64 is too large for 64-bit type 'long long unsigned int'
[...]

Reported-and-tested-by: Frank <fgndev@posteo.de>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/dmar.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 613b7153905d..071bb42bbbc5 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1354,7 +1354,6 @@ void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
 	struct qi_desc desc;
 
 	if (mask) {
-		WARN_ON_ONCE(addr & ((1ULL << (VTD_PAGE_SHIFT + mask)) - 1));
 		addr |= (1ULL << (VTD_PAGE_SHIFT + mask - 1)) - 1;
 		desc.qw1 = QI_DEV_IOTLB_ADDR(addr) | QI_DEV_IOTLB_SIZE;
 	} else
-- 
2.17.1


             reply	other threads:[~2020-01-16  1:54 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16  1:52 Lu Baolu [this message]
2020-01-16  1:52 ` [PATCH 1/1] iommu/vt-d: Remove unnecessary WARN_ON_ONCE() Lu Baolu
2020-01-17  9:59 ` Joerg Roedel
2020-01-17  9:59   ` Joerg Roedel
2020-01-18  2:14   ` Lu Baolu
2020-01-18  2:14     ` Lu Baolu
2020-01-24 14:36     ` Joerg Roedel
2020-01-24 14:36       ` Joerg Roedel

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