RDMA/rxe: support perf mgmt GET method

In RXE, hardware counters are already supported, but not in a
standardized manner. For instance, user-space monitoring tools like
atop only read from the *counters* directory. Therefore, it is
necessary to add perf management support to RXE.

Also use rxe_counter_get instead of raw atomic64_read in hw-counters.

Signed-off-by: zhenwei pi <zhenwei.pi@linux.dev>
Link: https://patch.msgid.link/20260414062948.671658-4-zhenwei.pi@linux.dev
Signed-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/sw/rxe/Makefile

@@ -23,6 +23,7 @@ rdma_rxe-y := \
 	rxe_task.o \
 	rxe_net.o \
 	rxe_hw_counters.o \
+	rxe_mad.o \
 	rxe_ns.o
 
 rdma_rxe-$(CONFIG_INFINIBAND_ON_DEMAND_PAGING) += rxe_odp.o

drivers/infiniband/sw/rxe/rxe_loc.h

@@ -242,4 +242,10 @@ static inline int rxe_ib_advise_mr(struct ib_pd *pd,
 
 #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
 
+/* rxe-mad.c */
+int rxe_process_mad(struct ib_device *ibdev, int mad_flags, u32 port_num,
+		    const struct ib_wc *in_wc, const struct ib_grh *in_grh,
+		    const struct ib_mad *in, struct ib_mad *out,
+		    size_t *out_mad_size, u16 *out_mad_pkey_index);
+
 #endif /* RXE_LOC_H */

drivers/infiniband/sw/rxe/rxe_mad.c

@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2026 zhenwei pi <zhenwei.pi@linux.dev>
+ */
+
+#include <rdma/ib_pma.h>
+#include "rxe.h"
+#include "rxe_hw_counters.h"
+
+static int rxe_get_pma_info(struct ib_mad *out)
+{
+	struct ib_class_port_info cpi = {};
+
+	cpi.capability_mask = IB_PMA_CLASS_CAP_EXT_WIDTH;
+	memcpy((out->data + 40), &cpi, sizeof(cpi));
+
+	return IB_MAD_RESULT_SUCCESS | IB_MAD_RESULT_REPLY;
+}
+
+static int rxe_get_pma_counters(struct rxe_dev *rxe, struct ib_mad *out)
+{
+	struct ib_pma_portcounters *pma_cnt = (struct ib_pma_portcounters *)(out->data + 40);
+	s64 val;
+
+	/* IBA release 1.8, 16.1.3.5: During operation, instead of overflowing, they shall stop
+	 * at all ones.
+	 */
+	val = atomic64_read(&rxe->stats_counters[RXE_CNT_LINK_DOWNED]);
+	pma_cnt->link_downed_counter = clamp(val, 0, U8_MAX);
+	return IB_MAD_RESULT_SUCCESS | IB_MAD_RESULT_REPLY;
+}
+
+static int rxe_get_pma_counters_ext(struct rxe_dev *rxe, struct ib_mad *out)
+{
+	struct ib_pma_portcounters_ext *pma_cnt_ext =
+		(struct ib_pma_portcounters_ext *)(out->data + 40);
+	s64 val;
+
+	val = atomic64_read(&rxe->stats_counters[RXE_CNT_SENT_BYTES]);
+	pma_cnt_ext->port_xmit_data = cpu_to_be64(val >> 2);
+
+	val = atomic64_read(&rxe->stats_counters[RXE_CNT_RCVD_BYTES]);
+	pma_cnt_ext->port_rcv_data = cpu_to_be64(val >> 2);
+
+	val = atomic64_read(&rxe->stats_counters[RXE_CNT_SENT_PKTS]);
+	pma_cnt_ext->port_xmit_packets = cpu_to_be64(val);
+
+	val = atomic64_read(&rxe->stats_counters[RXE_CNT_RCVD_PKTS]);
+	pma_cnt_ext->port_rcv_packets = cpu_to_be64(val);
+
+	return IB_MAD_RESULT_SUCCESS | IB_MAD_RESULT_REPLY;
+}
+
+static int rxe_get_perf_mgmt(struct rxe_dev *rxe, const struct ib_mad *in, struct ib_mad *out)
+{
+	switch (in->mad_hdr.attr_id) {
+	case IB_PMA_CLASS_PORT_INFO:
+		return rxe_get_pma_info(out);
+
+	case IB_PMA_PORT_COUNTERS:
+		return rxe_get_pma_counters(rxe, out);
+
+	case IB_PMA_PORT_COUNTERS_EXT:
+		return rxe_get_pma_counters_ext(rxe, out);
+
+	default:
+		out->mad_hdr.status = cpu_to_be16(IB_MGMT_MAD_STATUS_UNSUPPORTED_METHOD_ATTRIB);
+		return IB_MAD_RESULT_SUCCESS;
+	}
+}
+
+int rxe_process_mad(struct ib_device *ibdev, int mad_flags, u32 port_num,
+		    const struct ib_wc *in_wc, const struct ib_grh *in_grh,
+		    const struct ib_mad *in, struct ib_mad *out,
+		    size_t *out_mad_size, u16 *out_mad_pkey_index)
+{
+	struct rxe_dev *rxe = to_rdev(ibdev);
+	u8 mgmt_class = in->mad_hdr.mgmt_class;
+	u8 method = in->mad_hdr.method;
+
+	if (port_num != 1)
+		return IB_MAD_RESULT_FAILURE;
+
+	memset(out, 0, sizeof(*out));
+	switch (mgmt_class) {
+	case IB_MGMT_CLASS_PERF_MGMT:
+		if (method == IB_MGMT_METHOD_GET)
+			return rxe_get_perf_mgmt(rxe, in, out);
+		break;
+
+	default:
+		out->mad_hdr.status = cpu_to_be16(IB_MGMT_MAD_STATUS_UNSUPPORTED_METHOD);
+		return IB_MAD_RESULT_SUCCESS;
+	}
+
+	return IB_MAD_RESULT_SUCCESS | IB_MAD_RESULT_REPLY;
+}

drivers/infiniband/sw/rxe/rxe_verbs.c

@@ -1496,6 +1496,7 @@ static const struct ib_device_ops rxe_dev_ops = {
 	.post_recv = rxe_post_recv,
 	.post_send = rxe_post_send,
 	.post_srq_recv = rxe_post_srq_recv,
+	.process_mad = rxe_process_mad,
 	.query_ah = rxe_query_ah,
 	.query_device = rxe_query_device,
 	.query_pkey = rxe_query_pkey,