First-level translation restricts the input-address to a canonical address (i.e., address bits 63:N have the same value as address bit [N-1], where N is 48-bits with 4-level paging and 57-bits with 5-level paging). (section 3.6 in the spec) This makes first level IOVA canonical by using IOVA with bit [N-1] always cleared. Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> --- drivers/iommu/intel-iommu.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 54db6bc0b281..1ebf5ed460cf 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -3505,8 +3505,21 @@ static unsigned long intel_alloc_iova(struct device *dev, { unsigned long iova_pfn; - /* Restrict dma_mask to the width that the iommu can handle */ - dma_mask = min_t(uint64_t, DOMAIN_MAX_ADDR(domain->gaw), dma_mask); + /* + * Restrict dma_mask to the width that the iommu can handle. + * First-level translation restricts the input-address to a + * canonical address (i.e., address bits 63:N have the same + * value as address bit [N-1], where N is 48-bits with 4-level + * paging and 57-bits with 5-level paging). Hence, skip bit + * [N-1]. + */ + if (domain_use_first_level(domain)) + dma_mask = min_t(uint64_t, DOMAIN_MAX_ADDR(domain->gaw - 1), + dma_mask); + else + dma_mask = min_t(uint64_t, DOMAIN_MAX_ADDR(domain->gaw), + dma_mask); + /* Ensure we reserve the whole size-aligned region */ nrpages = __roundup_pow_of_two(nrpages); -- 2.17.1