diff --git a/source/adios2/toolkit/sst/dp/rdma_dp.c b/source/adios2/toolkit/sst/dp/rdma_dp.c
index 5de750abeb..3ec3139503 100644
--- a/source/adios2/toolkit/sst/dp/rdma_dp.c
+++ b/source/adios2/toolkit/sst/dp/rdma_dp.c
@@ -74,12 +74,16 @@ int sst_fi_mr_reg(
     CP_Services Svcs, void *CP_Stream,
     /* regular fi_mir_reg() parameters*/
     struct fid_domain *domain, const void *buf, size_t len, uint64_t acs, uint64_t offset,
-    uint64_t requested_key, uint64_t flags, struct fid_mr **mr, void *context,
+    uint64_t *requested_key, uint64_t flags, struct fid_mr **mr, void *context,
     /* additional parameters for binding the mr to the endpoint*/
     struct fid_ep *endpoint, int mr_mode)
 {
     *mr = NULL;
-    int res = fi_mr_reg(domain, buf, len, acs, offset, requested_key, flags, mr, context);
+    int res = fi_mr_reg(domain, buf, len, acs, offset, *requested_key, flags, mr, context);
+    if (*requested_key != 0)
+    {
+        ++*requested_key;
+    }
     int is_mr_endpoint = (mr_mode & FI_MR_ENDPOINT) != 0;
     if (!is_mr_endpoint)
     {
@@ -281,6 +285,7 @@ struct fabric_state
 #endif /* SST_HAVE_CRAY_DRC */
     struct cq_manual_progress *cq_manual_progress;
     pthread_t pthread_id;
+    uint64_t mr_key;
 };
 
 // Wrapper for fi_cq_sread to be called in its stead from the main thread.
@@ -591,15 +596,19 @@ static void init_fabric(struct fabric_state *fabric, struct _SstParams *Params,
      * (1) It does not support FI_MR_VIRT_ADDR.
      * (2) It requires use of FI_MR_ENDPOINT.
      *
+     * Some other providers again (e.g. psm3) don't support FI_MR_PROV_KEY.
+     *
      * So we propagate the bit value currently contained in the mr_mode
      * for these flags.
      */
     if (info->domain_attr->mr_mode != FI_MR_BASIC)
     {
-        info->domain_attr->mr_mode = FI_MR_ALLOCATED | FI_MR_PROV_KEY | FI_MR_LOCAL |
+        info->domain_attr->mr_mode = FI_MR_ALLOCATED | FI_MR_LOCAL |
+                                     (FI_MR_PROV_KEY & info->domain_attr->mr_mode) |
                                      (FI_MR_ENDPOINT & info->domain_attr->mr_mode) |
                                      (FI_MR_VIRT_ADDR & info->domain_attr->mr_mode);
         fabric->mr_virt_addr = info->domain_attr->mr_mode & FI_MR_VIRT_ADDR ? 1 : 0;
+        fabric->mr_key = info->domain_attr->mr_mode & FI_MR_PROV_KEY ? 0 : 1;
     }
     else
     {
@@ -1729,8 +1738,8 @@ static DP_WSR_Stream RdmaInitWriterPerReader(CP_Services Svcs, DP_WS_Stream WS_S
     ReaderRollHandle = &ContactInfo->ReaderRollHandle;
     ReaderRollHandle->Block = calloc(readerCohortSize, sizeof(struct _RdmaBuffer));
     sst_fi_mr_reg(Svcs, WS_Stream->CP_Stream, Fabric->domain, ReaderRollHandle->Block,
-                  readerCohortSize * sizeof(struct _RdmaBuffer), FI_REMOTE_WRITE, 0, 0, 0,
-                  &WSR_Stream->rrmr, Fabric->ctx, Fabric->signal,
+                  readerCohortSize * sizeof(struct _RdmaBuffer), FI_REMOTE_WRITE, 0,
+                  &Fabric->mr_key, 0, &WSR_Stream->rrmr, Fabric->ctx, Fabric->signal,
                   Fabric->info->domain_attr->mr_mode);
     ReaderRollHandle->Key = fi_mr_key(WSR_Stream->rrmr);
 
@@ -1869,8 +1878,8 @@ static ssize_t PostRead(CP_Services Svcs, Rdma_RS_Stream RS_Stream, int Rank, lo
     if (Fabric->local_mr_req)
     {
         // register dest buffer
-        sst_fi_mr_reg(Svcs, RS_Stream->CP_Stream, Fabric->domain, Buffer, Length, FI_READ, 0, 0, 0,
-                      &ret->LocalMR, Fabric->ctx, Fabric->signal,
+        sst_fi_mr_reg(Svcs, RS_Stream->CP_Stream, Fabric->domain, Buffer, Length, FI_READ, 0,
+                      &Fabric->mr_key, 0, &ret->LocalMR, Fabric->ctx, Fabric->signal,
                       Fabric->info->domain_attr->mr_mode);
         LocalDesc = fi_mr_desc(ret->LocalMR);
     }
@@ -2188,8 +2197,8 @@ static void RdmaProvideTimestep(CP_Services Svcs, DP_WS_Stream Stream_v, struct
     Entry->Desc = NULL;
 
     sst_fi_mr_reg(Svcs, Stream->CP_Stream, Fabric->domain, Data->block, Data->DataSize,
-                  FI_WRITE | FI_REMOTE_READ, 0, 0, 0, &Entry->mr, Fabric->ctx, Fabric->signal,
-                  Fabric->info->domain_attr->mr_mode);
+                  FI_WRITE | FI_REMOTE_READ, 0, &Fabric->mr_key, 0, &Entry->mr, Fabric->ctx,
+                  Fabric->signal, Fabric->info->domain_attr->mr_mode);
     Entry->Key = fi_mr_key(Entry->mr);
     if (Fabric->local_mr_req)
     {
@@ -2706,16 +2715,17 @@ static void PostPreload(CP_Services Svcs, Rdma_RS_Stream Stream, long Timestep)
     PreloadBuffer->BufferLen = 2 * StepLog->BufferSize;
     PreloadBuffer->Handle.Block = malloc(PreloadBuffer->BufferLen);
     sst_fi_mr_reg(Svcs, Stream->CP_Stream, Fabric->domain, PreloadBuffer->Handle.Block,
-                  PreloadBuffer->BufferLen, FI_REMOTE_WRITE, 0, 0, 0, &Stream->pbmr, Fabric->ctx,
-                  Fabric->signal, Fabric->info->domain_attr->mr_mode);
+                  PreloadBuffer->BufferLen, FI_REMOTE_WRITE, 0, &Fabric->mr_key, 0, &Stream->pbmr,
+                  Fabric->ctx, Fabric->signal, Fabric->info->domain_attr->mr_mode);
     PreloadKey = fi_mr_key(Stream->pbmr);
 
     SBSize = sizeof(*SendBuffer) * StepLog->WRanks;
     SendBuffer = malloc(SBSize);
     if (Fabric->local_mr_req)
     {
-        sst_fi_mr_reg(Svcs, Stream->CP_Stream, Fabric->domain, SendBuffer, SBSize, FI_WRITE, 0, 0,
-                      0, &sbmr, Fabric->ctx, Fabric->signal, Fabric->info->domain_attr->mr_mode);
+        sst_fi_mr_reg(Svcs, Stream->CP_Stream, Fabric->domain, SendBuffer, SBSize, FI_WRITE, 0,
+                      &Fabric->mr_key, 0, &sbmr, Fabric->ctx, Fabric->signal,
+                      Fabric->info->domain_attr->mr_mode);
         sbdesc = fi_mr_desc(sbmr);
     }
 
@@ -2724,7 +2734,7 @@ static void PostPreload(CP_Services Svcs, Rdma_RS_Stream Stream, long Timestep)
         RBLen = 2 * StepLog->Entries * DP_DATA_RECV_SIZE;
         Stream->RecvDataBuffer = malloc(RBLen);
         sst_fi_mr_reg(Svcs, Stream->CP_Stream, Fabric->domain, Stream->RecvDataBuffer, RBLen,
-                      FI_RECV, 0, 0, 0, &Stream->rbmr, Fabric->ctx, Fabric->signal,
+                      FI_RECV, 0, &Fabric->mr_key, 0, &Stream->rbmr, Fabric->ctx, Fabric->signal,
                       Fabric->info->domain_attr->mr_mode);
         Stream->rbdesc = fi_mr_desc(Stream->rbmr);
         RecvBuffer = (uint8_t *)Stream->RecvDataBuffer;
@@ -2750,8 +2760,8 @@ static void PostPreload(CP_Services Svcs, Rdma_RS_Stream Stream, long Timestep)
             RankLog->Buffer = (void *)RawPLBuffer;
             sst_fi_mr_reg(Svcs, Stream->CP_Stream, Fabric->domain, RankLog->ReqLog,
                           (sizeof(struct _RdmaBuffer) * RankLog->Entries) + sizeof(uint64_t),
-                          FI_REMOTE_READ, 0, 0, 0, &RankLog->preqbmr, Fabric->ctx, Fabric->signal,
-                          Fabric->info->domain_attr->mr_mode);
+                          FI_REMOTE_READ, 0, &Fabric->mr_key, 0, &RankLog->preqbmr, Fabric->ctx,
+                          Fabric->signal, Fabric->info->domain_attr->mr_mode);
             for (j = 0; j < RankLog->Entries; j++)
             {
                 ReqLog = &RankLog->ReqLog[j];
@@ -2894,8 +2904,8 @@ static void PullSelection(CP_Services Svcs, Rdma_WSR_Stream Stream)
     if (Fabric->local_mr_req)
     {
         sst_fi_mr_reg(Svcs, WS_Stream->CP_Stream, Fabric->domain, ReqBuffer.Handle.Block,
-                      ReqBuffer.BufferLen, FI_READ, 0, 0, 0, &rrmr, Fabric->ctx, Fabric->signal,
-                      Fabric->info->domain_attr->mr_mode);
+                      ReqBuffer.BufferLen, FI_READ, 0, &Fabric->mr_key, 0, &rrmr, Fabric->ctx,
+                      Fabric->signal, Fabric->info->domain_attr->mr_mode);
         rrdesc = fi_mr_desc(rrmr);
     }