iova_to_phys is a performance path for the DMA API and iommufd, implement it using an unrolled get_user_pages() like function waterfall scheme.
The implementation itself is fairly trivial.
Tested-by: Alejandro Jimenez alejandro.j.jimenez@oracle.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com --- drivers/iommu/generic_pt/iommu_pt.h | 105 ++++++++++++++++++++++++++++ include/linux/generic_pt/iommu.h | 34 +++++++-- 2 files changed, 134 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/generic_pt/iommu_pt.h b/drivers/iommu/generic_pt/iommu_pt.h index 03e1f3daa7a2ef..9413f868a65bfa 100644 --- a/drivers/iommu/generic_pt/iommu_pt.h +++ b/drivers/iommu/generic_pt/iommu_pt.h @@ -17,6 +17,111 @@
#define DOMAIN_NS(op) CONCATENATE(CONCATENATE(pt_iommu_, PTPFX), op)
+static int make_range_ul(struct pt_common *common, struct pt_range *range, + unsigned long iova, unsigned long len) +{ + unsigned long last; + + if (unlikely(len == 0)) + return -EINVAL; + + if (check_add_overflow(iova, len - 1, &last)) + return -EOVERFLOW; + + *range = pt_make_range(common, iova, last); + if (sizeof(iova) > sizeof(range->va)) { + if (unlikely(range->va != iova || range->last_va != last)) + return -EOVERFLOW; + } + return 0; +} + +static __maybe_unused int make_range_u64(struct pt_common *common, + struct pt_range *range, u64 iova, + u64 len) +{ + if (unlikely(iova > ULONG_MAX || len > ULONG_MAX)) + return -EOVERFLOW; + return make_range_ul(common, range, iova, len); +} + +/* + * Some APIs use unsigned long some use dma_addr_t as the type. Dispatch to the + * correct validation based on the type. + */ +#define make_range_no_check(common, range, iova, len) \ + ({ \ + int ret; \ + if (sizeof(iova) > sizeof(unsigned long) || \ + sizeof(len) > sizeof(unsigned long)) \ + ret = make_range_u64(common, range, iova, len); \ + else \ + ret = make_range_ul(common, range, iova, len); \ + ret; \ + }) + +#define make_range(common, range, iova, len) \ + ({ \ + int ret = make_range_no_check(common, range, iova, len); \ + if (!ret) \ + ret = pt_check_range(range); \ + ret; \ + }) + +static __always_inline int __do_iova_to_phys(struct pt_range *range, void *arg, + unsigned int level, + struct pt_table_p *table, + pt_level_fn_t descend_fn) +{ + struct pt_state pts = pt_init(range, level, table); + pt_oaddr_t *res = arg; + + switch (pt_load_single_entry(&pts)) { + case PT_ENTRY_EMPTY: + return -ENOENT; + case PT_ENTRY_TABLE: + return pt_descend(&pts, arg, descend_fn); + case PT_ENTRY_OA: + *res = pt_entry_oa_full(&pts); + return 0; + } + return -ENOENT; +} +PT_MAKE_LEVELS(__iova_to_phys, __do_iova_to_phys); + +/** + * iova_to_phys() - Return the output address for the given IOVA + * @iommu_table: Table to query + * @iova: IO virtual address to query + * + * Determine the output address from the given IOVA. @iova may have any + * alignment, the returned physical will be adjusted with any sub page offset. + * + * Context: The caller must hold a read range lock that includes @iova. + * + * Return: 0 if there is no translation for the given iova. + */ +phys_addr_t DOMAIN_NS(iova_to_phys)(struct iommu_domain *domain, + dma_addr_t iova) +{ + struct pt_iommu *iommu_table = + container_of(domain, struct pt_iommu, domain); + struct pt_range range; + pt_oaddr_t res; + int ret; + + ret = make_range(common_from_iommu(iommu_table), &range, iova, 1); + if (ret) + return ret; + + ret = pt_walk_range(&range, __iova_to_phys, &res); + /* PHYS_ADDR_MAX would be a better error code */ + if (ret) + return 0; + return res; +} +EXPORT_SYMBOL_NS_GPL(DOMAIN_NS(iova_to_phys), "GENERIC_PT_IOMMU"); + struct pt_iommu_collect_args { struct iommu_pages_list free_list; u8 ignore_mapped : 1; diff --git a/include/linux/generic_pt/iommu.h b/include/linux/generic_pt/iommu.h index b51de39c03c431..1fe5106997f833 100644 --- a/include/linux/generic_pt/iommu.h +++ b/include/linux/generic_pt/iommu.h @@ -116,11 +116,13 @@ struct pt_iommu_cfg { };
/* Generate the exported function signatures from iommu_pt.h */ -#define IOMMU_PROTOTYPES(fmt) \ - int pt_iommu_##fmt##_init(struct pt_iommu_##fmt *table, \ - const struct pt_iommu_##fmt##_cfg *cfg, \ - gfp_t gfp); \ - void pt_iommu_##fmt##_hw_info(struct pt_iommu_##fmt *table, \ +#define IOMMU_PROTOTYPES(fmt) \ + phys_addr_t pt_iommu_##fmt##_iova_to_phys(struct iommu_domain *domain, \ + dma_addr_t iova); \ + int pt_iommu_##fmt##_init(struct pt_iommu_##fmt *table, \ + const struct pt_iommu_##fmt##_cfg *cfg, \ + gfp_t gfp); \ + void pt_iommu_##fmt##_hw_info(struct pt_iommu_##fmt *table, \ struct pt_iommu_##fmt##_hw_info *info) #define IOMMU_FORMAT(fmt, member) \ struct pt_iommu_##fmt { \ @@ -129,6 +131,28 @@ struct pt_iommu_cfg { }; \ IOMMU_PROTOTYPES(fmt)
+/* + * A driver uses IOMMU_PT_DOMAIN_OPS to populate the iommu_domain_ops for the + * iommu_pt + */ +#define IOMMU_PT_DOMAIN_OPS(fmt) \ + .iova_to_phys = &pt_iommu_##fmt##_iova_to_phys, + +/* + * The driver should setup its domain struct like + * union { + * struct iommu_domain domain; + * struct pt_iommu_xxx xx; + * }; + * PT_IOMMU_CHECK_DOMAIN(struct mock_iommu_domain, xx.iommu, domain); + * + * Which creates an alias between driver_domain.domain and + * driver_domain.xx.iommu.domain. This is to avoid a mass rename of existing + * driver_domain.domain users. + */ +#define PT_IOMMU_CHECK_DOMAIN(s, pt_iommu_memb, domain_memb) \ + static_assert(offsetof(s, pt_iommu_memb.domain) == \ + offsetof(s, domain_memb))
struct pt_iommu_amdv1_cfg { struct pt_iommu_cfg common;