Hi Don,
This patch is not only for the sake of spec interpretation.
Till now I did not see any bugs , but it does not meant no bugs will appear
in the future. The address returned by dma_pte_addr is used in many places.
Thanks
Zhenhua
On 06/15/2013 04:16 AM, Don Dutile wrote:
On 05/23/2013 08:35 PM, Li, Zhen-Hua wrote:
In Intel Vt-D specs, Chapter 9.3 Page-Table Entry,
The size of ADDR(address) field is 12:51, but the function dma_pte_addr
treats it as 12:63.
Signed-off-by: Li, Zhen-Hua<[email protected]>
---
drivers/iommu/intel-iommu.c | 4 ++--
include/linux/dma_remapping.h | 2 ++
2 files changed, 4 insertions(+), 2 deletions(-)
Is this patching for the sake of spec interpretation?
a dma-pte format (consumed by iommu) has 63,61:52 as available for sw,
ignored by hw.
62 is 'transient mapping' bit, which is a _hint_ for selecting iotlbs
to flush sooner.
finally, the system would have to have a memory map that actually has
bit 62 set to
be affected.
So, for intel-iommu, I don't see a bug occurring.
Did you actually have one with previous definition, and if so,
could you provide that information ?
Cheers,
- Don
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index b4f0e28..c6d2847 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -311,10 +311,10 @@ static inline void dma_set_pte_prot(struct
dma_pte *pte, unsigned long prot)
static inline u64 dma_pte_addr(struct dma_pte *pte)
{
#ifdef CONFIG_64BIT
- return pte->val& VTD_PAGE_MASK;
+ return pte->val& DMA_PTE_MASK;
#else
/* Must have a full atomic 64-bit read */
- return __cmpxchg64(&pte->val, 0ULL, 0ULL)& VTD_PAGE_MASK;
+ return __cmpxchg64(&pte->val, 0ULL, 0ULL)& DMA_PTE_MASK;
#endif
}
diff --git a/include/linux/dma_remapping.h
b/include/linux/dma_remapping.h
index 57c9a8a..7a1e212 100644
--- a/include/linux/dma_remapping.h
+++ b/include/linux/dma_remapping.h
@@ -16,6 +16,8 @@
#define DMA_PTE_WRITE (2)
#define DMA_PTE_LARGE_PAGE (1<< 7)
#define DMA_PTE_SNP (1<< 11)
+#define DMA_PTE_ADD_LENGTH (40)
+#define DMA_PTE_MASK ((((u64)1<< DMA_PTE_ADD_LENGTH) - 1)<<
VTD_PAGE_SHIFT)
#define CONTEXT_TT_MULTI_LEVEL 0
#define CONTEXT_TT_DEV_IOTLB 1
.
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