Re: [PATCH v16 12/16] IB, arm64: untag user pointers in ib_uverbs_(re)reg_mr()
From: Andrey Konovalov <hidden>
Date: 2019-06-04 12:18:32
Also in:
amd-gfx, dri-devel, kvm, linux-kselftest, linux-media, linux-mm, linux-rdma, lkml
On Mon, Jun 3, 2019 at 7:46 PM Jason Gunthorpe [off-list ref] wrote:
On Mon, Jun 03, 2019 at 06:55:14PM +0200, Andrey Konovalov wrote:quoted
This patch is a part of a series that extends arm64 kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. ib_uverbs_(re)reg_mr() use provided user pointers for vma lookups (through e.g. mlx4_get_umem_mr()), which can only by done with untagged pointers. Untag user pointers in these functions. Signed-off-by: Andrey Konovalov <redacted> drivers/infiniband/core/uverbs_cmd.c | 4 ++++ 1 file changed, 4 insertions(+)diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index 5a3a1780ceea..f88ee733e617 100644 +++ b/drivers/infiniband/core/uverbs_cmd.c@@ -709,6 +709,8 @@ static int ib_uverbs_reg_mr(struct uverbs_attr_bundle *attrs) if (ret) return ret; + cmd.start = untagged_addr(cmd.start); + if ((cmd.start & ~PAGE_MASK) != (cmd.hca_va & ~PAGE_MASK)) return -EINVAL;I feel like we shouldn't thave to do this here, surely the cmd.start should flow unmodified to get_user_pages, and gup should untag it? ie, this sort of direction for the IB code (this would be a giant patch, so I didn't have time to write it all, but I think it is much saner):
Hi Jason, ib_uverbs_reg_mr() passes cmd.start to mlx4_get_umem_mr(), which calls find_vma(), which only accepts untagged addresses. Could you explain how your patch helps? Thanks!
quoted hunk ↗ jump to hunk
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index 54628ef879f0ce..7b3b736c87c253 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c@@ -193,7 +193,7 @@ EXPORT_SYMBOL(ib_umem_find_best_pgsz); * @access: IB_ACCESS_xxx flags for memory being pinned * @dmasync: flush in-flight DMA when the memory region is written */ -struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr, +struct ib_umem *ib_umem_get(struct ib_udata *udata, void __user *addr, size_t size, int access, int dmasync) { struct ib_ucontext *context;@@ -201,7 +201,7 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr, struct page **page_list; unsigned long lock_limit; unsigned long new_pinned; - unsigned long cur_base; + void __user *cur_base; struct mm_struct *mm; unsigned long npages; int ret;diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index 5a3a1780ceea4d..94389e7f12371f 100644 --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c@@ -735,7 +735,8 @@ static int ib_uverbs_reg_mr(struct uverbs_attr_bundle *attrs) } } - mr = pd->device->ops.reg_user_mr(pd, cmd.start, cmd.length, cmd.hca_va, + mr = pd->device->ops.reg_user_mr(pd, u64_to_user_ptr(cmd.start), + cmd.length, cmd.hca_va, cmd.access_flags, &attrs->driver_udata); if (IS_ERR(mr)) {diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c index 4d033796dcfcc2..bddbb952082fc5 100644 --- a/drivers/infiniband/hw/mlx5/mr.c +++ b/drivers/infiniband/hw/mlx5/mr.c@@ -786,7 +786,7 @@ static int mr_cache_max_order(struct mlx5_ib_dev *dev) } static int mr_umem_get(struct mlx5_ib_dev *dev, struct ib_udata *udata, - u64 start, u64 length, int access_flags, + void __user *start, u64 length, int access_flags, struct ib_umem **umem, int *npages, int *page_shift, int *ncont, int *order) {@@ -1262,8 +1262,8 @@ struct ib_mr *mlx5_ib_reg_dm_mr(struct ib_pd *pd, struct ib_dm *dm, attr->access_flags, mode); } -struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, - u64 virt_addr, int access_flags, +struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, void __user *start, + u64 length, u64 virt_addr, int access_flags, struct ib_udata *udata) { struct mlx5_ib_dev *dev = to_mdev(pd->device);diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index ec6446864b08e9..b3c8eaaa35c760 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h@@ -2464,8 +2464,8 @@ struct ib_device_ops { struct ib_mr *(*reg_user_mr)(struct ib_pd *pd, u64 start, u64 length, u64 virt_addr, int mr_access_flags, struct ib_udata *udata); - int (*rereg_user_mr)(struct ib_mr *mr, int flags, u64 start, u64 length, - u64 virt_addr, int mr_access_flags, + int (*rereg_user_mr)(struct ib_mr *mr, int flags, void __user *start, + u64 length, u64 virt_addr, int mr_access_flags, struct ib_pd *pd, struct ib_udata *udata); int (*dereg_mr)(struct ib_mr *mr, struct ib_udata *udata); struct ib_mr *(*alloc_mr)(struct ib_pd *pd, enum ib_mr_type mr_type,
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