IB/core: add support to create a unsafe global rkey to ib_create_pd

Instead of exposing ib_get_dma_mr to ULPs and letting them use it more or
less unchecked, this moves the capability of creating a global rkey into
the RDMA core, where it can be easily audited.  It also prints a warning
everytime this feature is used as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 19 insertions, 1 deletions

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 38a08dae49c4..4bdd898697cf 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1370,10 +1370,13 @@ struct ib_udata {
 
 struct ib_pd {
         u32                     local_dma_lkey;
+        u32                     flags;
         struct ib_device       *device;
         struct ib_uobject      *uobject;
         atomic_t                usecnt; /* count all resources */
 
+        u32                     unsafe_global_rkey;
+
         /*
          * Implementation details of the RDMA core, don't use in drivers:
          */
@@ -2506,8 +2509,23 @@ int ib_find_gid(struct ib_device *device, union ib_gid *gid,
 int ib_find_pkey(struct ib_device *device,
                  u8 port_num, u16 pkey, u16 *index);
 
-struct ib_pd *ib_alloc_pd(struct ib_device *device);
+enum ib_pd_flags {
+        /*
+         * Create a memory registration for all memory in the system and place
+         * the rkey for it into pd->unsafe_global_rkey.  This can be used by
+         * ULPs to avoid the overhead of dynamic MRs.
+         *
+         * This flag is generally considered unsafe and must only be used in
+         * extremly trusted environments.  Every use of it will log a warning
+         * in the kernel log.
+         */
+        IB_PD_UNSAFE_GLOBAL_RKEY        = 0x01,
+};
 
+struct ib_pd *__ib_alloc_pd(struct ib_device *device, unsigned int flags,
+                const char *caller);
+#define ib_alloc_pd(device, flags) \
+        __ib_alloc_pd((device), (flags), __func__)
 void ib_dealloc_pd(struct ib_pd *pd);
 
 /**