[PATCH 6/6] net/sfc: add support for MCDI proxy

[Andrew Rybchenko <arybchenko@solarflare.com>]

From: Ivan Malov <ivan.malov@oktetlabs.ru>

The patch is to add support for MCDI proxy which comes in
useful, particularly, while running over VF: few commands
will normally fail with EPERM, but in some cases the host
driver (i.e. running over the corresponding PF, typically,
within a hypervisor) may set itself as a proxy to conduct
authorization for the commands coming from VFs; these are
forwarded to the corresponding access control application
which may decline or approve authorization by replying to
the requests; all in all, the guest driver has to process
the replies forwarded back by the firmware MC in order to
give up gracefully (by setting return code which could be
understood by 'libefx') or re-issue the original commands

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
---
 drivers/net/sfc/efsys.h    |  2 +-
 drivers/net/sfc/sfc.h      |  2 ++
 drivers/net/sfc/sfc_mcdi.c | 74 ++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 71 insertions(+), 7 deletions(-)

diff --git a/drivers/net/sfc/efsys.h b/drivers/net/sfc/efsys.h
index 60829be..d52552b 100644
--- a/drivers/net/sfc/efsys.h
+++ b/drivers/net/sfc/efsys.h
@@ -177,7 +177,7 @@ prefetch_read_once(const volatile void *addr)
 /* MCDI is required for SFN7xxx and SFN8xx */
 #define EFSYS_OPT_MCDI 1
 #define EFSYS_OPT_MCDI_LOGGING 1
-#define EFSYS_OPT_MCDI_PROXY_AUTH 0
+#define EFSYS_OPT_MCDI_PROXY_AUTH 1
 
 #define EFSYS_OPT_MAC_STATS 1
 
diff --git a/drivers/net/sfc/sfc.h b/drivers/net/sfc/sfc.h
index 204a054..5c633c8 100644
--- a/drivers/net/sfc/sfc.h
+++ b/drivers/net/sfc/sfc.h
@@ -125,6 +125,8 @@ struct sfc_mcdi {
 	enum sfc_mcdi_state		state;
 	efx_mcdi_transport_t		transport;
 	bool				logging;
+	uint32_t			proxy_handle;
+	efx_rc_t			proxy_result;
 };
 
 struct sfc_intr {
diff --git a/drivers/net/sfc/sfc_mcdi.c b/drivers/net/sfc/sfc_mcdi.c
index 3bed2e0..43dbf13 100644
--- a/drivers/net/sfc/sfc_mcdi.c
+++ b/drivers/net/sfc/sfc_mcdi.c
@@ -36,6 +36,7 @@
 #include "sfc.h"
 #include "sfc_log.h"
 #include "sfc_kvargs.h"
+#include "sfc_ev.h"
 
 #define SFC_MCDI_POLL_INTERVAL_MIN_US	10		/* 10us in 1us units */
 #define SFC_MCDI_POLL_INTERVAL_MAX_US	(US_PER_S / 10)	/* 100ms in 1us units */
@@ -49,8 +50,22 @@ sfc_mcdi_timeout(struct sfc_adapter *sa)
 	sfc_panic(sa, "MCDI timeout handling is not implemented\n");
 }
 
+static inline boolean_t
+sfc_mcdi_proxy_event_available(struct sfc_adapter *sa)
+{
+	struct sfc_mcdi *mcdi = &sa->mcdi;
+
+	mcdi->proxy_handle = 0;
+	mcdi->proxy_result = ETIMEDOUT;
+	sfc_ev_mgmt_qpoll(sa);
+	if (mcdi->proxy_result != ETIMEDOUT)
+		return B_TRUE;
+
+	return B_FALSE;
+}
+
 static void
-sfc_mcdi_poll(struct sfc_adapter *sa)
+sfc_mcdi_poll(struct sfc_adapter *sa, boolean_t proxy)
 {
 	efx_nic_t *enp;
 	unsigned int delay_total;
@@ -62,13 +77,20 @@ sfc_mcdi_poll(struct sfc_adapter *sa)
 	enp = sa->nic;
 
 	do {
-		if (efx_mcdi_request_poll(enp))
+		boolean_t poll_completed;
+
+		poll_completed = (proxy) ? sfc_mcdi_proxy_event_available(sa) :
+					   efx_mcdi_request_poll(enp);
+		if (poll_completed)
 			return;
 
 		if (delay_total > SFC_MCDI_WATCHDOG_INTERVAL_US) {
-			aborted = efx_mcdi_request_abort(enp);
-			SFC_ASSERT(aborted);
-			sfc_mcdi_timeout(sa);
+			if (!proxy) {
+				aborted = efx_mcdi_request_abort(enp);
+				SFC_ASSERT(aborted);
+				sfc_mcdi_timeout(sa);
+			}
+
 			return;
 		}
 
@@ -90,13 +112,42 @@ sfc_mcdi_execute(void *arg, efx_mcdi_req_t *emrp)
 {
 	struct sfc_adapter *sa = (struct sfc_adapter *)arg;
 	struct sfc_mcdi *mcdi = &sa->mcdi;
+	uint32_t proxy_handle;
 
 	rte_spinlock_lock(&mcdi->lock);
 
 	SFC_ASSERT(mcdi->state == SFC_MCDI_INITIALIZED);
 
 	efx_mcdi_request_start(sa->nic, emrp, B_FALSE);
-	sfc_mcdi_poll(sa);
+	sfc_mcdi_poll(sa, B_FALSE);
+
+	if (efx_mcdi_get_proxy_handle(sa->nic, emrp, &proxy_handle) == 0) {
+		/*
+		 * Authorization is required for the MCDI request;
+		 * wait for an MCDI proxy response event to bring
+		 * a non-zero proxy handle (should be the same as
+		 * the value obtained above) and operation status
+		 */
+		sfc_mcdi_poll(sa, B_TRUE);
+
+		if ((mcdi->proxy_handle != 0) &&
+		    (mcdi->proxy_handle != proxy_handle)) {
+			sfc_err(sa, "Unexpected MCDI proxy event");
+			emrp->emr_rc = EFAULT;
+		} else if (mcdi->proxy_result == 0) {
+			/*
+			 * Authorization succeeded; re-issue the original
+			 * request and poll for an ordinary MCDI response
+			 */
+			efx_mcdi_request_start(sa->nic, emrp, B_FALSE);
+			sfc_mcdi_poll(sa, B_FALSE);
+		} else {
+			emrp->emr_rc = mcdi->proxy_result;
+			sfc_err(sa, "MCDI proxy authorization failed "
+				    "(handle=%08x, result=%d)",
+				    proxy_handle, mcdi->proxy_result);
+		}
+	}
 
 	rte_spinlock_unlock(&mcdi->lock);
 }
@@ -185,6 +236,16 @@ sfc_mcdi_logger(void *arg, efx_log_msg_t type,
 	}
 }
 
+static void
+sfc_mcdi_ev_proxy_response(void *arg, uint32_t handle, efx_rc_t result)
+{
+	struct sfc_adapter *sa = (struct sfc_adapter *)arg;
+	struct sfc_mcdi *mcdi = &sa->mcdi;
+
+	mcdi->proxy_handle = handle;
+	mcdi->proxy_result = result;
+}
+
 int
 sfc_mcdi_init(struct sfc_adapter *sa)
 {
@@ -222,6 +283,7 @@ sfc_mcdi_init(struct sfc_adapter *sa)
 	emtp->emt_ev_cpl = sfc_mcdi_ev_cpl;
 	emtp->emt_exception = sfc_mcdi_exception;
 	emtp->emt_logger = sfc_mcdi_logger;
+	emtp->emt_ev_proxy_response = sfc_mcdi_ev_proxy_response;
 
 	sfc_log_init(sa, "init MCDI");
 	rc = efx_mcdi_init(sa->nic, emtp);
-- 
2.9.3