[Qemu-devel] [PATCH 1/4] hw/rdma: Add SRQ support to backend layer

[Kamal Heib]

Add the required function and definitions for support shared receive
queues (SRQs) in the backend layer.

Signed-off-by: Kamal Heib <address@hidden>
---
 hw/rdma/rdma_backend.c      | 115 +++++++++++++++++++++++++++++++++++-
 hw/rdma/rdma_backend.h      |  12 ++++
 hw/rdma/rdma_backend_defs.h |   5 ++
 3 files changed, 130 insertions(+), 2 deletions(-)

diff --git a/hw/rdma/rdma_backend.c b/hw/rdma/rdma_backend.c
index d1660b6474fa..d75872256207 100644
--- a/hw/rdma/rdma_backend.c
+++ b/hw/rdma/rdma_backend.c
@@ -40,6 +40,7 @@ typedef struct BackendCtx {
     void *up_ctx;
     struct ibv_sge sge; /* Used to save MAD recv buffer */
     RdmaBackendQP *backend_qp; /* To maintain recv buffers */
+    RdmaBackendSRQ *backend_srq;
 } BackendCtx;
 
 struct backend_umad {
@@ -116,8 +117,13 @@ static int rdma_poll_cq(RdmaDeviceResources *rdma_dev_res, 
struct ibv_cq *ibcq)
 
             comp_handler(bctx->up_ctx, &wc[i]);
 
-            rdma_protected_gslist_remove_int32(&bctx->backend_qp->cqe_ctx_list,
-                                               wc[i].wr_id);
+        if (bctx->backend_qp) {
+                
rdma_protected_gslist_remove_int32(&bctx->backend_qp->cqe_ctx_list,
+                                                   wc[i].wr_id);
+        } else {
+                
rdma_protected_gslist_remove_int32(&bctx->backend_srq->cqe_ctx_list,
+                                                   wc[i].wr_id);
+        }
             rdma_rm_dealloc_cqe_ctx(rdma_dev_res, wc[i].wr_id);
             g_free(bctx);
         }
@@ -662,6 +668,60 @@ err_free_bctx:
     g_free(bctx);
 }
 
+void rdma_backend_post_srq_recv(RdmaBackendDev *backend_dev,
+                                RdmaBackendSRQ *srq, struct ibv_sge *sge,
+                                uint32_t num_sge, void *ctx)
+{
+    BackendCtx *bctx;
+    struct ibv_sge new_sge[MAX_SGE];
+    uint32_t bctx_id;
+    int rc;
+    struct ibv_recv_wr wr = {}, *bad_wr;
+
+    bctx = g_malloc0(sizeof(*bctx));
+    bctx->up_ctx = ctx;
+    bctx->backend_srq = srq;
+    bctx->backend_qp = NULL;
+
+    rc = rdma_rm_alloc_cqe_ctx(backend_dev->rdma_dev_res, &bctx_id, bctx);
+    if (unlikely(rc)) {
+        complete_work(IBV_WC_GENERAL_ERR, VENDOR_ERR_NOMEM, ctx);
+        goto err_free_bctx;
+    }
+
+    rdma_protected_gslist_append_int32(&srq->cqe_ctx_list, bctx_id);
+
+    rc = build_host_sge_array(backend_dev->rdma_dev_res, new_sge, sge, num_sge,
+                              &backend_dev->rdma_dev_res->stats.rx_bufs_len);
+    if (rc) {
+        complete_work(IBV_WC_GENERAL_ERR, rc, ctx);
+        goto err_dealloc_cqe_ctx;
+    }
+
+    wr.num_sge = num_sge;
+    wr.sg_list = new_sge;
+    wr.wr_id = bctx_id;
+    rc = ibv_post_srq_recv(srq->ibsrq, &wr, &bad_wr);
+    if (rc) {
+        rdma_error_report("ibv_post_srq_recv failed, srqn=0x%x, rc=%d, 
errno=%d",
+                          srq->ibsrq->handle, rc, errno);
+        complete_work(IBV_WC_GENERAL_ERR, VENDOR_ERR_FAIL_BACKEND, ctx);
+        goto err_dealloc_cqe_ctx;
+    }
+
+    atomic_inc(&backend_dev->rdma_dev_res->stats.missing_cqe);
+    backend_dev->rdma_dev_res->stats.rx_bufs++;
+
+    return;
+
+err_dealloc_cqe_ctx:
+    backend_dev->rdma_dev_res->stats.rx_bufs_err++;
+    rdma_rm_dealloc_cqe_ctx(backend_dev->rdma_dev_res, bctx_id);
+
+err_free_bctx:
+    g_free(bctx);
+}
+
 int rdma_backend_create_pd(RdmaBackendDev *backend_dev, RdmaBackendPD *pd)
 {
     pd->ibpd = ibv_alloc_pd(backend_dev->context);
@@ -938,6 +998,55 @@ void rdma_backend_destroy_qp(RdmaBackendQP *qp, 
RdmaDeviceResources *dev_res)
     rdma_protected_gslist_destroy(&qp->cqe_ctx_list);
 }
 
+int rdma_backend_create_srq(RdmaBackendSRQ *srq, RdmaBackendPD *pd,
+                            uint32_t max_wr, uint32_t max_sge,
+                            uint32_t srq_limit)
+{
+    struct ibv_srq_init_attr srq_init_attr = {};
+
+    srq_init_attr.attr.max_wr = max_wr;
+    srq_init_attr.attr.max_sge = max_sge;
+    srq_init_attr.attr.srq_limit = srq_limit;
+
+    srq->ibsrq = ibv_create_srq(pd->ibpd, &srq_init_attr);
+    if (!srq->ibsrq) {
+        rdma_error_report("ibv_create_srq failed, errno=%d", errno);
+        return -EIO;
+    }
+
+    rdma_protected_gslist_init(&srq->cqe_ctx_list);
+
+    return 0;
+}
+
+int rdma_backend_query_srq(RdmaBackendSRQ *srq, struct ibv_srq_attr *srq_attr)
+{
+    if (!srq->ibsrq) {
+        return -EINVAL;
+    }
+
+    return ibv_query_srq(srq->ibsrq, srq_attr);
+}
+
+int rdma_backend_modify_srq(RdmaBackendSRQ *srq, struct ibv_srq_attr *srq_attr,
+                int srq_attr_mask)
+{
+    if (!srq->ibsrq) {
+        return -EINVAL;
+    }
+
+    return ibv_modify_srq(srq->ibsrq, srq_attr, srq_attr_mask);
+}
+
+void rdma_backend_destroy_srq(RdmaBackendSRQ *srq, RdmaDeviceResources 
*dev_res)
+{
+    if (srq->ibsrq) {
+        ibv_destroy_srq(srq->ibsrq);
+    }
+    g_slist_foreach(srq->cqe_ctx_list.list, free_cqe_ctx, dev_res);
+    rdma_protected_gslist_destroy(&srq->cqe_ctx_list);
+}
+
 #define CHK_ATTR(req, dev, member, fmt) ({ \
     trace_rdma_check_dev_attr(#member, dev.member, req->member); \
     if (req->member > dev.member) { \
@@ -960,6 +1069,7 @@ static int init_device_caps(RdmaBackendDev *backend_dev,
     }
 
     dev_attr->max_sge = MAX_SGE;
+    dev_attr->max_srq_sge = MAX_SGE;
 
     CHK_ATTR(dev_attr, bk_dev_attr, max_mr_size, "%" PRId64);
     CHK_ATTR(dev_attr, bk_dev_attr, max_qp, "%d");
@@ -970,6 +1080,7 @@ static int init_device_caps(RdmaBackendDev *backend_dev,
     CHK_ATTR(dev_attr, bk_dev_attr, max_qp_rd_atom, "%d");
     CHK_ATTR(dev_attr, bk_dev_attr, max_qp_init_rd_atom, "%d");
     CHK_ATTR(dev_attr, bk_dev_attr, max_ah, "%d");
+    CHK_ATTR(dev_attr, bk_dev_attr, max_srq, "%d");
 
     return 0;
 }
diff --git a/hw/rdma/rdma_backend.h b/hw/rdma/rdma_backend.h
index 38056d97c7fc..cad7956d98e8 100644
--- a/hw/rdma/rdma_backend.h
+++ b/hw/rdma/rdma_backend.h
@@ -114,4 +114,16 @@ void rdma_backend_post_recv(RdmaBackendDev *backend_dev,
                             RdmaBackendQP *qp, uint8_t qp_type,
                             struct ibv_sge *sge, uint32_t num_sge, void *ctx);
 
+int rdma_backend_create_srq(RdmaBackendSRQ *srq, RdmaBackendPD *pd,
+                            uint32_t max_wr, uint32_t max_sge,
+                            uint32_t srq_limit);
+int rdma_backend_query_srq(RdmaBackendSRQ *srq, struct ibv_srq_attr *srq_attr);
+int rdma_backend_modify_srq(RdmaBackendSRQ *srq, struct ibv_srq_attr *srq_attr,
+                            int srq_attr_mask);
+void rdma_backend_destroy_srq(RdmaBackendSRQ *srq,
+                              RdmaDeviceResources *dev_res);
+void rdma_backend_post_srq_recv(RdmaBackendDev *backend_dev,
+                                RdmaBackendSRQ *srq, struct ibv_sge *sge,
+                                uint32_t num_sge, void *ctx);
+
 #endif
diff --git a/hw/rdma/rdma_backend_defs.h b/hw/rdma/rdma_backend_defs.h
index 817153dc8cf4..0b55be35038d 100644
--- a/hw/rdma/rdma_backend_defs.h
+++ b/hw/rdma/rdma_backend_defs.h
@@ -68,4 +68,9 @@ typedef struct RdmaBackendQP {
     RdmaProtectedGSList cqe_ctx_list;
 } RdmaBackendQP;
 
+typedef struct RdmaBackendSRQ {
+    struct ibv_srq *ibsrq;
+    RdmaProtectedGSList cqe_ctx_list;
+} RdmaBackendSRQ;
+
 #endif
-- 
2.20.1