[dpdk-stable] [PATCH 1/4] common/mlx5: share UAR allocation routine

[dpdk-stable] [PATCH 1/4] common/mlx5: share UAR allocation routine

[Viacheslav Ovsiienko]

This patch introduces the routine to allocate the UAR (User
Access Region) with various memory mapping types. The origin
patch being fixed provided the UAR allocation workaround
for the mlx5 net PMD only. As it was found the other mlx5
based drivers - vdpa and regex are affected by the issue
as well and must be fixed.

Fixes: a0bfe9d56f74 ("net/mlx5: fix UAR memory mapping type")
Cc: stable@dpdk.org

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
---
 drivers/common/mlx5/mlx5_common.c    | 98 ++++++++++++++++++++++++++++++++++++
 drivers/common/mlx5/mlx5_common.h    |  2 +
 drivers/common/mlx5/mlx5_devx_cmds.h |  8 +++
 drivers/common/mlx5/version.map      |  1 +
 drivers/net/mlx5/mlx5_defs.h         |  9 ----
 5 files changed, 109 insertions(+), 9 deletions(-)

diff --git a/drivers/common/mlx5/mlx5_common.c b/drivers/common/mlx5/mlx5_common.c
index 06f0a64..d2bdf29 100644
--- a/drivers/common/mlx5/mlx5_common.c
+++ b/drivers/common/mlx5/mlx5_common.c
@@ -244,3 +244,101 @@ static inline void mlx5_cpu_id(unsigned int level,
 	}
 	return ret;
 }
+
+/**
+ * Allocate the User Access Region with DevX on specified device.
+ *
+ * @param [in] ctx
+ *   Infiniband device context to perform allocation on.
+ * @param [in] mapping
+ *   MLX5DV_UAR_ALLOC_TYPE_BF - allocate as cached memory with write-combining
+ *				attributes (if supported by the host), the
+ *				writes to the UAR registers must be followed
+ *				by write memory barrier.
+ *   MLX5DV_UAR_ALLOC_TYPE_NC - allocate as non-cached nenory, all writes are
+ *				promoted to the registers immediately, no
+ *				memory barriers needed.
+ *   mapping < 0 - the first attempt is performed with MLX5DV_UAR_ALLOC_TYPE_BF,
+ *		   if this fails the next attempt with MLX5DV_UAR_ALLOC_TYPE_NC
+ *		   is performed. The drivers specifying negative values should
+ *		   always provide the write memory barrier operation after UAR
+ *		   register writings.
+ * If there is no definitions for the MLX5DV_UAR_ALLOC_TYPE_xx (older rdma
+ * library headers), the caller can specify 0.
+ *
+ * @return
+ *   UAR object pointer on success, NULL otherwise and rte_errno is set.
+ */
+void *
+mlx5_devx_alloc_uar(void *ctx, int mapping)
+{
+	void *uar;
+	uint32_t retry, uar_mapping;
+	void *base_addr;
+
+	for (retry = 0; retry < MLX5_ALLOC_UAR_RETRY; ++retry) {
+#ifdef MLX5DV_UAR_ALLOC_TYPE_NC
+		/* Control the mapping type according to the settings. */
+		uar_mapping = (mapping < 0) ?
+			      MLX5DV_UAR_ALLOC_TYPE_NC : mapping;
+#else
+		/*
+		 * It seems we have no way to control the memory mapping type
+		 * for the UAR, the default "Write-Combining" type is supposed.
+		 */
+		uar_mapping = 0;
+#endif
+		uar = mlx5_glue->devx_alloc_uar(ctx, uar_mapping);
+#ifdef MLX5DV_UAR_ALLOC_TYPE_NC
+		if (!uar &&
+		    mapping < 0 &&
+		    uar_mapping == MLX5DV_UAR_ALLOC_TYPE_BF) {
+			/*
+			 * In some environments like virtual machine the
+			 * Write Combining mapped might be not supported and
+			 * UAR allocation fails. We tried "Non-Cached" mapping
+			 * for the case.
+			 */
+			DRV_LOG(WARNING, "Failed to allocate DevX UAR (BF)");
+			uar_mapping = MLX5DV_UAR_ALLOC_TYPE_NC;
+			uar = mlx5_glue->devx_alloc_uar(ctx, uar_mapping);
+		} else if (!uar &&
+			   mapping < 0 &&
+			   uar_mapping == MLX5DV_UAR_ALLOC_TYPE_NC) {
+			/*
+			 * If Verbs/kernel does not support "Non-Cached"
+			 * try the "Write-Combining".
+			 */
+			DRV_LOG(WARNING, "Failed to allocate DevX UAR (NC)");
+			uar_mapping = MLX5DV_UAR_ALLOC_TYPE_BF;
+			uar = mlx5_glue->devx_alloc_uar(ctx, uar_mapping);
+		}
+#endif
+		if (!uar) {
+			DRV_LOG(ERR, "Failed to allocate DevX UAR (BF/NC)");
+			rte_errno = ENOMEM;
+			goto exit;
+		}
+		base_addr = mlx5_os_get_devx_uar_base_addr(uar);
+		if (base_addr)
+			break;
+		/*
+		 * The UARs are allocated by rdma_core within the
+		 * IB device context, on context closure all UARs
+		 * will be freed, should be no memory/object leakage.
+		 */
+		DRV_LOG(WARNING, "Retrying to allocate DevX UAR");
+		uar = NULL;
+	}
+	/* Check whether we finally succeeded with valid UAR allocation. */
+	if (!uar) {
+		DRV_LOG(ERR, "Failed to allocate DevX UAR (NULL base)");
+		rte_errno = ENOMEM;
+	}
+	/*
+	 * Return void * instead of struct mlx5dv_devx_uar *
+	 * is for compatibility with older rdma-core library headers.
+	 */
+exit:
+	return uar;
+}
diff --git a/drivers/common/mlx5/mlx5_common.h b/drivers/common/mlx5/mlx5_common.h
index 9d226e5..10a0851 100644
--- a/drivers/common/mlx5/mlx5_common.h
+++ b/drivers/common/mlx5/mlx5_common.h
@@ -261,6 +261,8 @@ int64_t mlx5_get_dbr(void *ctx,  struct mlx5_dbr_page_list *head,
 __rte_internal
 int32_t mlx5_release_dbr(struct mlx5_dbr_page_list *head, uint32_t umem_id,
 			 uint64_t offset);
+__rte_internal
+void *mlx5_devx_alloc_uar(void *ctx, int mapping);
 extern uint8_t haswell_broadwell_cpu;
 
 __rte_internal
diff --git a/drivers/common/mlx5/mlx5_devx_cmds.h b/drivers/common/mlx5/mlx5_devx_cmds.h
index 8d66f1d..726e9f5 100644
--- a/drivers/common/mlx5/mlx5_devx_cmds.h
+++ b/drivers/common/mlx5/mlx5_devx_cmds.h
@@ -8,6 +8,14 @@
 #include "mlx5_glue.h"
 #include "mlx5_prm.h"
 
+/*
+ * Defines the amount of retries to allocate the first UAR in the page.
+ * OFED 5.0.x and Upstream rdma_core before v29 returned the NULL as
+ * UAR base address if UAR was not the first object in the UAR page.
+ * It caused the PMD failure and we should try to get another UAR
+ * till we get the first one with non-NULL base address returned.
+ */
+#define MLX5_ALLOC_UAR_RETRY 32
 
 /* This is limitation of libibverbs: in length variable type is u16. */
 #define MLX5_DEVX_MAX_KLM_ENTRIES ((UINT16_MAX - \
diff --git a/drivers/common/mlx5/version.map b/drivers/common/mlx5/version.map
index af182e6..17dd11f 100644
--- a/drivers/common/mlx5/version.map
+++ b/drivers/common/mlx5/version.map
@@ -40,6 +40,7 @@ INTERNAL {
 	mlx5_devx_cmd_query_virtq;
 	mlx5_devx_cmd_register_read;
 	mlx5_devx_get_out_command_status;
+	mlx5_devx_alloc_uar;
 
 	mlx5_get_ifname_sysfs;
 	mlx5_get_dbr;
diff --git a/drivers/net/mlx5/mlx5_defs.h b/drivers/net/mlx5/mlx5_defs.h
index f8f8a1f..aa55db3 100644
--- a/drivers/net/mlx5/mlx5_defs.h
+++ b/drivers/net/mlx5/mlx5_defs.h
@@ -204,13 +204,4 @@
 #define static_assert _Static_assert
 #endif
 
-/*
- * Defines the amount of retries to allocate the first UAR in the page.
- * OFED 5.0.x and Upstream rdma_core before v29 returned the NULL as
- * UAR base address if UAR was not the first object in the UAR page.
- * It caused the PMD failure and we should try to get another UAR
- * till we get the first one with non-NULL base address returned.
- */
-#define MLX5_ALLOC_UAR_RETRY 32
-
 #endif /* RTE_PMD_MLX5_DEFS_H_ */
-- 
1.8.3.1

[dpdk-stable] [PATCH 2/4] regex/mlx5: fix UAR allocation

[Viacheslav Ovsiienko]

This patch provides the UAR allocation workaround for the
hosts where UAR allocation with Write-Combining memory
mapping type fails.

Fixes: b34d816363b5 ("regex/mlx5: support rules import")
Cc: stable@dpdk.org

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
---
 drivers/regex/mlx5/mlx5_regex.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/regex/mlx5/mlx5_regex.c b/drivers/regex/mlx5/mlx5_regex.c
index 17590b9..05048e7 100644
--- a/drivers/regex/mlx5/mlx5_regex.c
+++ b/drivers/regex/mlx5/mlx5_regex.c
@@ -176,7 +176,12 @@
 		rte_errno = ENOMEM;
 		goto error;
 	}
-	priv->uar = mlx5_glue->devx_alloc_uar(ctx, 0);
+	/*
+	 * This PMD always claims the write memory barrier on UAR
+	 * registers writings, it is safe to allocate UAR with any
+	 * memory mapping type.
+	 */
+	priv->uar = mlx5_devx_alloc_uar(ctx, -1);
 	if (!priv->uar) {
 		DRV_LOG(ERR, "can't allocate uar.");
 		rte_errno = ENOMEM;
-- 
1.8.3.1

[dpdk-stable] [PATCH 3/4] vdpa/mlx5: fix UAR allocation

[Viacheslav Ovsiienko]

This patch provides the UAR allocation workaround for the
hosts where UAR allocation with Write-Combining memory
mapping type fails.

Fixes: 8395927cdfaf ("vdpa/mlx5: prepare HW queues")
Cc: stable@dpdk.org

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
---
 drivers/vdpa/mlx5/mlx5_vdpa_event.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/mlx5/mlx5_vdpa_event.c b/drivers/vdpa/mlx5/mlx5_vdpa_event.c
index 010543c..3aeaeb8 100644
--- a/drivers/vdpa/mlx5/mlx5_vdpa_event.c
+++ b/drivers/vdpa/mlx5/mlx5_vdpa_event.c
@@ -77,7 +77,12 @@
 		DRV_LOG(ERR, "Failed to change event channel FD.");
 		goto error;
 	}
-	priv->uar = mlx5_glue->devx_alloc_uar(priv->ctx, 0);
+	/*
+	 * This PMD always claims the write memory barrier on UAR
+	 * registers writings, it is safe to allocate UAR with any
+	 * memory mapping type.
+	 */
+	priv->uar = mlx5_devx_alloc_uar(priv->ctx, -1);
 	if (!priv->uar) {
 		rte_errno = errno;
 		DRV_LOG(ERR, "Failed to allocate UAR.");
-- 
1.8.3.1

Re: [dpdk-stable] [PATCH 1/4] common/mlx5: share UAR allocation routine

[Thomas Monjalon]

10/11/2020 17:04, Viacheslav Ovsiienko:
> This patch introduces the routine to allocate the UAR (User
> Access Region) with various memory mapping types. The origin
> patch being fixed provided the UAR allocation workaround
> for the mlx5 net PMD only. As it was found the other mlx5
> based drivers - vdpa and regex are affected by the issue
> as well and must be fixed.
> 
> Fixes: a0bfe9d56f74 ("net/mlx5: fix UAR memory mapping type")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>

Series applied, thanks

Re: [dpdk-stable] [PATCH 1/4] common/mlx5: share UAR allocation routine

[Thomas Monjalon]

10/11/2020 17:04, Viacheslav Ovsiienko:
> +void *
> +mlx5_devx_alloc_uar(void *ctx, int mapping)
> +{
> +	void *uar;
> +	uint32_t retry, uar_mapping;
> +	void *base_addr;
> +
> +	for (retry = 0; retry < MLX5_ALLOC_UAR_RETRY; ++retry) {
> +#ifdef MLX5DV_UAR_ALLOC_TYPE_NC
> +		/* Control the mapping type according to the settings. */
> +		uar_mapping = (mapping < 0) ?
> +			      MLX5DV_UAR_ALLOC_TYPE_NC : mapping;
> +#else
> +		/*
> +		 * It seems we have no way to control the memory mapping type
> +		 * for the UAR, the default "Write-Combining" type is supposed.
> +		 */
> +		uar_mapping = 0;
> +#endif

A failure was reported by the CI:
	error: unused parameter ‘mapping’
It is fixed while merging by adding the below in the #else case:
	RTE_SET_USED(mapping);

Please take care of CI results!