svn commit: r341062 - head/sys/dev/sfxge/common

[Andrew Rybchenko]

Author: arybchik
Date: Tue Nov 27 14:15:30 2018
New Revision: 341062
URL: https://svnweb.freebsd.org/changeset/base/341062

Log:
  sfxge(4): use MAC stats DMA buffer size when decoding
  
  On Medford2 and later the MAC stats buffer has been enlarged.
  Use the MAC stats DMA buffer size to ensure that the stats END
  generation count is read from the correct location, and that
  over-reading of the DMA buffer is prevented.
  
  Submitted by:   Andy Moreton <amoreton at solarflare.com>
  Sponsored by:   Solarflare Communications, Inc.
  Differential Revision:  https://reviews.freebsd.org/D18176

Modified:
  head/sys/dev/sfxge/common/ef10_mac.c
  head/sys/dev/sfxge/common/siena_mac.c

Modified: head/sys/dev/sfxge/common/ef10_mac.c
==============================================================================
--- head/sys/dev/sfxge/common/ef10_mac.c	Tue Nov 27 14:15:19 2018	(r341061)
+++ head/sys/dev/sfxge/common/ef10_mac.c	Tue Nov 27 14:15:30 2018	(r341062)
@@ -579,16 +579,45 @@ ef10_mac_stats_update(
 	__inout_ecount(EFX_MAC_NSTATS)	efsys_stat_t *stat,
 	__inout_opt			uint32_t *generationp)
 {
-	efx_qword_t value;
+	const efx_nic_cfg_t *encp = &enp->en_nic_cfg;
 	efx_qword_t generation_start;
 	efx_qword_t generation_end;
+	efx_qword_t value;
+	efx_rc_t rc;
 
-	_NOTE(ARGUNUSED(enp))
+	/*
+	 * The MAC_STATS contain start and end generation counters used to
+	 * detect when the DMA buffer has been updated during stats decode.
+	 * All stats counters are 64bit unsigned values.
+	 *
+	 * Siena-compatible MAC stats contain MC_CMD_MAC_NSTATS 64bit counters.
+	 * The generation end counter is at index MC_CMD_MAC_GENERATION_END
+	 * (same as MC_CMD_MAC_NSTATS-1).
+	 *
+	 * Medford2 and later use a larger DMA buffer: MAC_STATS_NUM_STATS from
+	 * MC_CMD_GET_CAPABILITIES_V4_OUT reports the number of 64bit counters.
+	 *
+	 * Firmware writes the generation end counter as the last counter in the
+	 * DMA buffer. Do not use MC_CMD_MAC_GENERATION_END, as that is only
+	 * correct for legacy Siena-compatible MAC stats.
+	 */
 
+	if (encp->enc_mac_stats_nstats < MC_CMD_MAC_NSTATS) {
+		/* MAC stats count too small for legacy MAC stats */
+		rc = ENOSPC;
+		goto fail1;
+	}
+	if (EFSYS_MEM_SIZE(esmp) <
+	    (encp->enc_mac_stats_nstats * sizeof (efx_qword_t))) {
+		/* DMA buffer too small */
+		rc = ENOSPC;
+		goto fail2;
+	}
+
 	/* Read END first so we don't race with the MC */
-	EFSYS_DMA_SYNC_FOR_KERNEL(esmp, 0, EFX_MAC_STATS_SIZE);
-	EF10_MAC_STAT_READ(esmp, MC_CMD_MAC_GENERATION_END,
-			    &generation_end);
+	EFSYS_DMA_SYNC_FOR_KERNEL(esmp, 0, EFSYS_MEM_SIZE(esmp));
+	EF10_MAC_STAT_READ(esmp, (encp->enc_mac_stats_nstats - 1),
+	    &generation_end);
 	EFSYS_MEM_READ_BARRIER();
 
 	/* TX */
@@ -878,8 +907,8 @@ ef10_mac_stats_update(
 	EF10_MAC_STAT_READ(esmp, MC_CMD_MAC_VADAPTER_TX_OVERFLOW, &value);
 	EFSYS_STAT_SET_QWORD(&(stat[EFX_MAC_VADAPTER_TX_OVERFLOW]), &value);
 
-
-	EFSYS_DMA_SYNC_FOR_KERNEL(esmp, 0, EFX_MAC_STATS_SIZE);
+	/* Read START generation counter */
+	EFSYS_DMA_SYNC_FOR_KERNEL(esmp, 0, EFSYS_MEM_SIZE(esmp));
 	EFSYS_MEM_READ_BARRIER();
 	EF10_MAC_STAT_READ(esmp, MC_CMD_MAC_GENERATION_START,
 			    &generation_start);
@@ -894,6 +923,13 @@ ef10_mac_stats_update(
 		*generationp = EFX_QWORD_FIELD(generation_start, EFX_DWORD_0);
 
 	return (0);
+
+fail2:
+	EFSYS_PROBE(fail2);
+fail1:
+	EFSYS_PROBE1(fail1, efx_rc_t, rc);
+
+	return (rc);
 }
 
 #endif	/* EFSYS_OPT_MAC_STATS */

Modified: head/sys/dev/sfxge/common/siena_mac.c
==============================================================================
--- head/sys/dev/sfxge/common/siena_mac.c	Tue Nov 27 14:15:19 2018	(r341061)
+++ head/sys/dev/sfxge/common/siena_mac.c	Tue Nov 27 14:15:30 2018	(r341062)
@@ -274,16 +274,28 @@ siena_mac_stats_update(
 	__inout_ecount(EFX_MAC_NSTATS)	efsys_stat_t *stat,
 	__inout_opt			uint32_t *generationp)
 {
-	efx_qword_t value;
+	const efx_nic_cfg_t *encp = &enp->en_nic_cfg;
 	efx_qword_t generation_start;
 	efx_qword_t generation_end;
+	efx_qword_t value;
+	efx_rc_t rc;
 
-	_NOTE(ARGUNUSED(enp))
+	if (encp->enc_mac_stats_nstats < MC_CMD_MAC_NSTATS) {
+		/* MAC stats count too small */
+		rc = ENOSPC;
+		goto fail1;
+	}
+	if (EFSYS_MEM_SIZE(esmp) <
+	    (encp->enc_mac_stats_nstats * sizeof (efx_qword_t))) {
+		/* DMA buffer too small */
+		rc = ENOSPC;
+		goto fail2;
+	}
 
 	/* Read END first so we don't race with the MC */
-	EFSYS_DMA_SYNC_FOR_KERNEL(esmp, 0, EFX_MAC_STATS_SIZE);
-	SIENA_MAC_STAT_READ(esmp, MC_CMD_MAC_GENERATION_END,
-			    &generation_end);
+	EFSYS_DMA_SYNC_FOR_KERNEL(esmp, 0, EFSYS_MEM_SIZE(esmp));
+	SIENA_MAC_STAT_READ(esmp, (encp->enc_mac_stats_nstats - 1),
+	    &generation_end);
 	EFSYS_MEM_READ_BARRIER();
 
 	/* TX */
@@ -466,6 +478,13 @@ siena_mac_stats_update(
 		*generationp = EFX_QWORD_FIELD(generation_start, EFX_DWORD_0);
 
 	return (0);
+
+fail2:
+	EFSYS_PROBE(fail2);
+fail1:
+	EFSYS_PROBE1(fail1, efx_rc_t, rc);
+
+	return (rc);
 }
 
 #endif	/* EFSYS_OPT_MAC_STATS */