lkml.org 
[lkml]   [2020]   [Feb]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.19 160/191] iommu/vt-d: Remove unnecessary WARN_ON_ONCE()
Date
From: Lu Baolu <baolu.lu@linux.intel.com>

[ Upstream commit 857f081426e5aa38313426c13373730f1345fe95 ]

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>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/dmar.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 7f9824b0609e7..72994d67bc5b9 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1345,7 +1345,6 @@ 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.high = QI_DEV_IOTLB_ADDR(addr) | QI_DEV_IOTLB_SIZE;
} else
--
2.20.1


\
 
 \ /
  Last update: 2020-02-21 09:24    [W:0.746 / U:0.572 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site