On Tue, Sep 26, 2017 at 03:22:47PM +0100, Robin Murphy wrote:
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 6784a05dd6b2..d7f7def81613 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -2254,10 +2254,12 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
> uint64_t tmp;
>
> if (!sg_res) {
> + size_t off = sg->offset & ~PAGE_MASK;
Should this be VTD_PAGE_MASK?
> +
> sg_res = aligned_nrpages(sg->offset, sg->length);
> - sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + sg->offset;
> + sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + off;
> sg->dma_length = sg->length;
> - pteval = page_to_phys(sg_page(sg)) | prot;
> + pteval = (page_to_phys(sg_page(sg)) + sg->offset - off) | prot;
Something seems wrong here.. sg->offset can be > VTD_PAGE_SIZE, think
we should add sg->offset and then find the pteval?
attached below another cut at fixing the same problem.. if there is something
obvious i missed, let me know.
again.. untested :-)
Cheers,
Ashok
Sometimes offset can be greater than 4K. vt-d needs to account for that.
From: Ashok Raj <ashok.raj@xxxxxxxxx>
Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx>
---
drivers/iommu/intel-iommu.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 6784a05..d43b566 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2254,10 +2254,13 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
uint64_t tmp;
if (!sg_res) {
+ size_t off = sg->offset & ~VTD_PAGE_SHIFT;
sg_res = aligned_nrpages(sg->offset, sg->length);
- sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + sg->offset;
+ sg->dma_address = ((dma_addr_t)
+ (iov_pfn + sg->offset) << VTD_PAGE_SHIFT) + off;
sg->dma_length = sg->length;
- pteval = page_to_phys(sg_page(sg)) | prot;
+ pteval = (page_to_phys(sg_page(sg)) +
+ (sg->offset << VTD_PAGE_SHIFT)) | prot;
phys_pfn = pteval >> VTD_PAGE_SHIFT;
}
