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mlxsw: Add support for new reset flow

PATCH In review Petr Machata 3 participants 30 messages Nov 15, 2023 – Nov 18, 2023

Subsystems (7)
Networking Network drivers Kselftest PCI +3 more subsystems
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Petr Machata

author maintainer
#0 lore raw

cover mlxsw: Add support for new reset flow

Ido Schimmel writes:

This patchset changes mlxsw to issue a PCI reset during probe and devlink reload so that the PCI firmware could be upgraded without a reboot.

Unlike the old version of this patchset [1], in this version the driver no longer tries to issue a PCI reset by triggering a PCI link toggle on its own, but instead calls the PCI core to issue the reset.

The PCI APIs require the device lock to be held which is why patches #1-#6 adjust devlink to acquire the device lock during reload.

Patches #7 adds reset method quirk for NVIDIA Spectrum devices.

Patch #8 adds a debug level print in PCI core so that device ready delay will be printed even if it is shorter than one second.

Patches #9-#11 are straightforward preparations in mlxsw.

Patch #12 finally implements the new reset flow in mlxsw.

Patch #13 adds PCI reset handlers in mlxsw to avoid user space from resetting the device from underneath an unaware driver. Instead, the driver is gracefully de-initialized before the PCI reset and then initialized again after it.

Patch #14 adds a PCI reset selftest to make sure this code path does not regress.

[1] https://lore.kernel.org/netdev/[email protected]/

Amit Cohen (3):
mlxsw: Extend MRSR pack() function to support new commands
mlxsw: pci: Rename mlxsw_pci_sw_reset()
mlxsw: pci: Move software reset code to a separate function

Ido Schimmel (11):
devlink: Move private netlink flags to C file
devlink: Acquire device lock during netns dismantle
devlink: Enable the use of private flags in post_doit operations
devlink: Allow taking device lock in pre_doit operations
devlink: Acquire device lock during reload command
devlink: Add device lock assert in reload operation
PCI: Add no PM reset quirk for NVIDIA Spectrum devices
PCI: Add debug print for device ready delay
mlxsw: pci: Add support for new reset flow
mlxsw: pci: Implement PCI reset handlers
selftests: mlxsw: Add PCI reset test

 Documentation/netlink/specs/devlink.yaml      |  4 +-
 drivers/net/ethernet/mellanox/mlxsw/pci.c     | 90 +++++++++++++++++--
 drivers/net/ethernet/mellanox/mlxsw/reg.h     | 16 +++-
 drivers/pci/pci.c                             |  3 +
 drivers/pci/quirks.c                          | 13 +++
 net/devlink/core.c                            |  4 +-
 net/devlink/dev.c                             |  8 ++
 net/devlink/devl_internal.h                   | 21 ++++-
 net/devlink/health.c                          |  3 +-
 net/devlink/netlink.c                         | 47 +++++++---
 net/devlink/netlink_gen.c                     |  4 +-
 net/devlink/netlink_gen.h                     |  5 ++
 net/devlink/region.c                          |  3 +-
 .../selftests/drivers/net/mlxsw/pci_reset.sh  | 58 ++++++++++++
 14 files changed, 248 insertions(+), 31 deletions(-)
 create mode 100755 tools/testing/selftests/drivers/net/mlxsw/pci_reset.sh
Signature · 1 line
2.41.0
author maintainer
#1 lore raw

PATCH 1/14 devlink: Move private netlink flags to C file

From: Ido Schimmel <[email protected]>

The flags are not used outside of the C file so move them there.

Suggested-by Jiri Pirko <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 net/devlink/devl_internal.h | 3 ---
 net/devlink/netlink.c       | 3 +++
 2 files changed, 3 insertions(+), 3 deletions(-)
net/devlink/devl_internal.h +0 -3
index 183dbe3807ab..2a9b263300a4 100644
@@ -111,9 +111,6 @@ int devlink_rel_devlink_handle_put(struct sk_buff *msg, struct devlink *devlink,
 				   bool *msg_updated);
 
 /* Netlink */
-#define DEVLINK_NL_FLAG_NEED_PORT		BIT(0)
-#define DEVLINK_NL_FLAG_NEED_DEVLINK_OR_PORT	BIT(1)
-
 enum devlink_multicast_groups {
 	DEVLINK_MCGRP_CONFIG,
 };
net/devlink/netlink.c +3 -0
index d0b90ebc8b15..7350138c8bb4 100644
@@ -9,6 +9,9 @@
 
 #include "devl_internal.h"
 
+#define DEVLINK_NL_FLAG_NEED_PORT		BIT(0)
+#define DEVLINK_NL_FLAG_NEED_DEVLINK_OR_PORT	BIT(1)
+
 static const struct genl_multicast_group devlink_nl_mcgrps[] = {
 	[DEVLINK_MCGRP_CONFIG] = { .name = DEVLINK_GENL_MCGRP_CONFIG_NAME },
 };
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 1/14
#2 lore raw

Re: [PATCH net-next 01/14] devlink: Move private netlink flags to C file

Quoted 8 lines · Petr Machata

From: Ido Schimmel <[email protected]>

The flags are not used outside of the C file so move them there.

Suggested-by Jiri Pirko <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#3 lore raw

PATCH 2/14 devlink: Acquire device lock during netns dismantle

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

Device drivers register with devlink from their probe routines (under the device lock) by acquiring the devlink instance lock and calling devl_register().

Drivers that support a devlink reload usually implement the reload_{down, up}() operations in a similar fashion to their remove and probe routines, respectively.

However, while the remove and probe routines are invoked with the device lock held, the reload operations are only invoked with the devlink instance lock held. It is therefore impossible for drivers to acquire the device lock from their reload operations, as this would result in lock inversion.

The motivating use case for invoking the reload operations with the device lock held is in mlxsw which needs to trigger a PCI reset as part of the reload. The driver cannot call pci_reset_function() as this function acquires the device lock. Instead, it needs to call __pci_reset_function_locked which expects the device lock to be held.

To that end, adjust devlink to always acquire the device lock before the devlink instance lock when performing a reload.

For now, only do that when reload is triggered as part of netns dismantle. Subsequent patches will handle the case where reload is explicitly triggered by user space.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 net/devlink/core.c          |  4 ++--
 net/devlink/devl_internal.h | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)
net/devlink/core.c +2 -2
index 6984877e9f10..4275a2bc6d8e 100644
@@ -503,14 +503,14 @@ static void __net_exit devlink_pernet_pre_exit(struct net *net)
 	 * all devlink instances from this namespace into init_net.
 	 */
 	devlinks_xa_for_each_registered_get(net, index, devlink) {
-		devl_lock(devlink);
+		devl_dev_lock(devlink, true);
 		err = 0;
 		if (devl_is_registered(devlink))
 			err = devlink_reload(devlink, &init_net,
 					     DEVLINK_RELOAD_ACTION_DRIVER_REINIT,
 					     DEVLINK_RELOAD_LIMIT_UNSPEC,
 					     &actions_performed, NULL);
-		devl_unlock(devlink);
+		devl_dev_unlock(devlink, true);
 		devlink_put(devlink);
 		if (err && err != -EOPNOTSUPP)
 			pr_warn("Failed to reload devlink instance into init_net\n");
net/devlink/devl_internal.h +15 -0
index 2a9b263300a4..178abaf74a10 100644
@@ -3,6 +3,7 @@
  * Copyright (c) 2016 Jiri Pirko <[email protected]>
  */
 
+#include <linux/device.h>
 #include <linux/etherdevice.h>
 #include <linux/mutex.h>
 #include <linux/netdevice.h>

@@ -96,6 +97,20 @@ static inline bool devl_is_registered(struct devlink *devlink)
 	return xa_get_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
 }
 
+static inline void devl_dev_lock(struct devlink *devlink, bool dev_lock)
+{
+	if (dev_lock)
+		device_lock(devlink->dev);
+	devl_lock(devlink);
+}
+
+static inline void devl_dev_unlock(struct devlink *devlink, bool dev_lock)
+{
+	devl_unlock(devlink);
+	if (dev_lock)
+		device_unlock(devlink->dev);
+}
+
 typedef void devlink_rel_notify_cb_t(struct devlink *devlink, u32 obj_index);
 typedef void devlink_rel_cleanup_cb_t(struct devlink *devlink, u32 obj_index,
 				      u32 rel_index);
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 2/14
#4 lore raw

Re: [PATCH net-next 02/14] devlink: Acquire device lock during netns dismantle

Quoted 25 lines · Petr Machata

From: Ido Schimmel <[email protected]>

Device drivers register with devlink from their probe routines (under the device lock) by acquiring the devlink instance lock and calling devl_register().

Drivers that support a devlink reload usually implement the reload_{down, up}() operations in a similar fashion to their remove and probe routines, respectively.

However, while the remove and probe routines are invoked with the device lock held, the reload operations are only invoked with the devlink instance lock held. It is therefore impossible for drivers to acquire the device lock from their reload operations, as this would result in lock inversion.

The motivating use case for invoking the reload operations with the device lock held is in mlxsw which needs to trigger a PCI reset as part of the reload. The driver cannot call pci_reset_function() as this function acquires the device lock. Instead, it needs to call __pci_reset_function_locked which expects the device lock to be held.

To that end, adjust devlink to always acquire the device lock before the devlink instance lock when performing a reload.

Quoted 7 lines

For now, only do that when reload is triggered as part of netns dismantle. Subsequent patches will handle the case where reload is explicitly triggered by user space.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#5 lore raw

PATCH 3/14 devlink: Enable the use of private flags in post_doit operations

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

Currently, private flags (e.g., 'DEVLINK_NL_FLAG_NEED_PORT') are only used in pre_doit operations, but a subsequent patch will need to conditionally lock and unlock the device lock in pre and post doit operations, respectively.

As a preparation, enable the use of private flags in post_doit operations in a similar fashion to how it is done for pre_doit operations.

No functional changes intended.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 net/devlink/netlink.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)
net/devlink/netlink.c +11 -5
index 7350138c8bb4..5bb6624f3288 100644
@@ -141,14 +141,20 @@ int devlink_nl_pre_doit_port_optional(const struct genl_split_ops *ops,
 	return __devlink_nl_pre_doit(skb, info, DEVLINK_NL_FLAG_NEED_DEVLINK_OR_PORT);
 }
 
+static void __devlink_nl_post_doit(struct sk_buff *skb, struct genl_info *info,
+				   u8 flags)
+{
+	struct devlink *devlink;
+
+	devlink = info->user_ptr[0];
+	devl_unlock(devlink);
+	devlink_put(devlink);
+}
+
 void devlink_nl_post_doit(const struct genl_split_ops *ops,
 			  struct sk_buff *skb, struct genl_info *info)
 {
-	struct devlink *devlink;
-
-	devlink = info->user_ptr[0];
-	devl_unlock(devlink);
-	devlink_put(devlink);
+	__devlink_nl_post_doit(skb, info, 0);
 }
 
 static int devlink_nl_inst_single_dumpit(struct sk_buff *msg,
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 3/14
#6 lore raw

Re: [PATCH net-next 03/14] devlink: Enable the use of private flags in post_doit operations

Quoted 11 lines · Petr Machata

From: Ido Schimmel <[email protected]>

Currently, private flags (e.g., 'DEVLINK_NL_FLAG_NEED_PORT') are only used in pre_doit operations, but a subsequent patch will need to conditionally lock and unlock the device lock in pre and post doit operations, respectively.

As a preparation, enable the use of private flags in post_doit operations in a similar fashion to how it is done for pre_doit operations.

Quoted 5 lines

No functional changes intended.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#7 lore raw

PATCH 4/14 devlink: Allow taking device lock in pre_doit operations

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

Introduce a new private flag ('DEVLINK_NL_FLAG_NEED_DEV_LOCK') to allow netlink commands to specify that they need to acquire the device lock in their pre_doit operation and release it in their post_doit operation.

The reload command will use this flag in the subsequent patch.

No functional changes intended.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 net/devlink/devl_internal.h |  3 ++-
 net/devlink/health.c        |  3 ++-
 net/devlink/netlink.c       | 19 ++++++++++++-------
 net/devlink/region.c        |  3 ++-
 4 files changed, 18 insertions(+), 10 deletions(-)
net/devlink/devl_internal.h +2 -1
index 178abaf74a10..5ea2e2012e93 100644
@@ -152,7 +152,8 @@ typedef int devlink_nl_dump_one_func_t(struct sk_buff *msg,
 				       int flags);
 
 struct devlink *
-devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs);
+devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs,
+			    bool dev_lock);
 
 int devlink_nl_dumpit(struct sk_buff *msg, struct netlink_callback *cb,
 		      devlink_nl_dump_one_func_t *dump_one);
net/devlink/health.c +2 -1
index 695df61f8ac2..71ae121dc739 100644
@@ -1151,7 +1151,8 @@ devlink_health_reporter_get_from_cb_lock(struct netlink_callback *cb)
 	struct nlattr **attrs = info->attrs;
 	struct devlink *devlink;
 
-	devlink = devlink_get_from_attrs_lock(sock_net(cb->skb->sk), attrs);
+	devlink = devlink_get_from_attrs_lock(sock_net(cb->skb->sk), attrs,
+					      false);
 	if (IS_ERR(devlink))
 		return NULL;
net/devlink/netlink.c +12 -7
index 5bb6624f3288..86f12531bf99 100644
@@ -11,6 +11,7 @@
 
 #define DEVLINK_NL_FLAG_NEED_PORT		BIT(0)
 #define DEVLINK_NL_FLAG_NEED_DEVLINK_OR_PORT	BIT(1)
+#define DEVLINK_NL_FLAG_NEED_DEV_LOCK		BIT(2)
 
 static const struct genl_multicast_group devlink_nl_mcgrps[] = {
 	[DEVLINK_MCGRP_CONFIG] = { .name = DEVLINK_GENL_MCGRP_CONFIG_NAME },

@@ -64,7 +65,8 @@ int devlink_nl_msg_reply_and_new(struct sk_buff **msg, struct genl_info *info)
 }
 
 struct devlink *
-devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs)
+devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs,
+			    bool dev_lock)
 {
 	struct devlink *devlink;
 	unsigned long index;

@@ -78,12 +80,12 @@ devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs)
 	devname = nla_data(attrs[DEVLINK_ATTR_DEV_NAME]);
 
 	devlinks_xa_for_each_registered_get(net, index, devlink) {
-		devl_lock(devlink);
+		devl_dev_lock(devlink, dev_lock);
 		if (devl_is_registered(devlink) &&
 		    strcmp(devlink->dev->bus->name, busname) == 0 &&
 		    strcmp(dev_name(devlink->dev), devname) == 0)
 			return devlink;
-		devl_unlock(devlink);
+		devl_dev_unlock(devlink, dev_lock);
 		devlink_put(devlink);
 	}
 

@@ -93,11 +95,13 @@ devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs)
 static int __devlink_nl_pre_doit(struct sk_buff *skb, struct genl_info *info,
 				 u8 flags)
 {
+	bool dev_lock = flags & DEVLINK_NL_FLAG_NEED_DEV_LOCK;
 	struct devlink_port *devlink_port;
 	struct devlink *devlink;
 	int err;
 
-	devlink = devlink_get_from_attrs_lock(genl_info_net(info), info->attrs);
+	devlink = devlink_get_from_attrs_lock(genl_info_net(info), info->attrs,
+					      dev_lock);
 	if (IS_ERR(devlink))
 		return PTR_ERR(devlink);
 

@@ -117,7 +121,7 @@ static int __devlink_nl_pre_doit(struct sk_buff *skb, struct genl_info *info,
 	return 0;
 
 unlock:
-	devl_unlock(devlink);
+	devl_dev_unlock(devlink, dev_lock);
 	devlink_put(devlink);
 	return err;
 }

@@ -144,10 +148,11 @@ int devlink_nl_pre_doit_port_optional(const struct genl_split_ops *ops,
 static void __devlink_nl_post_doit(struct sk_buff *skb, struct genl_info *info,
 				   u8 flags)
 {
+	bool dev_lock = flags & DEVLINK_NL_FLAG_NEED_DEV_LOCK;
 	struct devlink *devlink;
 
 	devlink = info->user_ptr[0];
-	devl_unlock(devlink);
+	devl_dev_unlock(devlink, dev_lock);
 	devlink_put(devlink);
 }
 

@@ -165,7 +170,7 @@ static int devlink_nl_inst_single_dumpit(struct sk_buff *msg,
 	struct devlink *devlink;
 	int err;
 
-	devlink = devlink_get_from_attrs_lock(sock_net(msg->sk), attrs);
+	devlink = devlink_get_from_attrs_lock(sock_net(msg->sk), attrs, false);
 	if (IS_ERR(devlink))
 		return PTR_ERR(devlink);
 	err = dump_one(msg, devlink, cb, flags | NLM_F_DUMP_FILTERED);
net/devlink/region.c +2 -1
index 0aab7b82d678..e3bab458db94 100644
@@ -883,7 +883,8 @@ int devlink_nl_region_read_dumpit(struct sk_buff *skb,
 
 	start_offset = state->start_offset;
 
-	devlink = devlink_get_from_attrs_lock(sock_net(cb->skb->sk), attrs);
+	devlink = devlink_get_from_attrs_lock(sock_net(cb->skb->sk), attrs,
+					      false);
 	if (IS_ERR(devlink))
 		return PTR_ERR(devlink);
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 4/14
#8 lore raw

Re: [PATCH net-next 04/14] devlink: Allow taking device lock in pre_doit operations

Quoted 6 lines · Petr Machata

From: Ido Schimmel <[email protected]>

Introduce a new private flag ('DEVLINK_NL_FLAG_NEED_DEV_LOCK') to allow netlink commands to specify that they need to acquire the device lock in their pre_doit operation and release it in their post_doit operation.

Quoted 7 lines

The reload command will use this flag in the subsequent patch.

No functional changes intended.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>

...

net/devlink/netlink.c devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs) · line 98

Quoted 5 lines
net/devlink/netlink.c +1 -0
@@ -93,11 +95,13 @@ devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs)
 static int __devlink_nl_pre_doit(struct sk_buff *skb, struct genl_info *info,
 				 u8 flags)
 {
+	bool dev_lock = flags & DEVLINK_NL_FLAG_NEED_DEV_LOCK;

nit: I would have expressed the above as follows, to convert
the integer to a bool. But I understand that it makes no difference in this case so there is no need to update the patch for this:

bool dev_lock = !!(flags & DEVLINK_NL_FLAG_NEED_DEV_LOCK);

...

author maintainer
#9 lore raw

PATCH 5/14 devlink: Acquire device lock during reload command

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

Device drivers register with devlink from their probe routines (under the device lock) by acquiring the devlink instance lock and calling devl_register().

Drivers that support a devlink reload usually implement the reload_{down, up}() operations in a similar fashion to their remove and probe routines, respectively.

However, while the remove and probe routines are invoked with the device lock held, the reload operations are only invoked with the devlink instance lock held. It is therefore impossible for drivers to acquire the device lock from their reload operations, as this would result in lock inversion.

The motivating use case for invoking the reload operations with the device lock held is in mlxsw which needs to trigger a PCI reset as part of the reload. The driver cannot call pci_reset_function() as this function acquires the device lock. Instead, it needs to call __pci_reset_function_locked which expects the device lock to be held.

To that end, adjust devlink to always acquire the device lock before the devlink instance lock when performing a reload.

Do that when reload is explicitly triggered by user space by specifying the 'DEVLINK_NL_FLAG_NEED_DEV_LOCK' flag in the pre_doit and post_doit operations of the reload command.

A previous patch already handled the case where reload is invoked as part of netns dismantle.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 Documentation/netlink/specs/devlink.yaml |  4 ++--
 net/devlink/netlink.c                    | 13 +++++++++++++
 net/devlink/netlink_gen.c                |  4 ++--
 net/devlink/netlink_gen.h                |  5 +++++
 4 files changed, 22 insertions(+), 4 deletions(-)
Documentation/netlink/specs/devlink.yaml +2 -2
index 572d83a414d0..43067e1f63aa 100644
@@ -1484,8 +1484,8 @@ operations:
       dont-validate: [ strict ]
       flags: [ admin-perm ]
       do:
-        pre: devlink-nl-pre-doit
-        post: devlink-nl-post-doit
+        pre: devlink-nl-pre-doit-dev-lock
+        post: devlink-nl-post-doit-dev-lock
         request:
           attributes:
             - bus-name
net/devlink/netlink.c +13 -0
index 86f12531bf99..fa9afe3e6d9b 100644
@@ -138,6 +138,12 @@ int devlink_nl_pre_doit_port(const struct genl_split_ops *ops,
 	return __devlink_nl_pre_doit(skb, info, DEVLINK_NL_FLAG_NEED_PORT);
 }
 
+int devlink_nl_pre_doit_dev_lock(const struct genl_split_ops *ops,
+				 struct sk_buff *skb, struct genl_info *info)
+{
+	return __devlink_nl_pre_doit(skb, info, DEVLINK_NL_FLAG_NEED_DEV_LOCK);
+}
+
 int devlink_nl_pre_doit_port_optional(const struct genl_split_ops *ops,
 				      struct sk_buff *skb,
 				      struct genl_info *info)

@@ -162,6 +168,13 @@ void devlink_nl_post_doit(const struct genl_split_ops *ops,
 	__devlink_nl_post_doit(skb, info, 0);
 }
 
+void
+devlink_nl_post_doit_dev_lock(const struct genl_split_ops *ops,
+			      struct sk_buff *skb, struct genl_info *info)
+{
+	__devlink_nl_post_doit(skb, info, DEVLINK_NL_FLAG_NEED_DEV_LOCK);
+}
+
 static int devlink_nl_inst_single_dumpit(struct sk_buff *msg,
 					 struct netlink_callback *cb, int flags,
 					 devlink_nl_dump_one_func_t *dump_one,
net/devlink/netlink_gen.c +2 -2
index 788dfdc498a9..95f9b4350ab7 100644
@@ -846,9 +846,9 @@ const struct genl_split_ops devlink_nl_ops[73] = {
 	{
 		.cmd		= DEVLINK_CMD_RELOAD,
 		.validate	= GENL_DONT_VALIDATE_STRICT,
-		.pre_doit	= devlink_nl_pre_doit,
+		.pre_doit	= devlink_nl_pre_doit_dev_lock,
 		.doit		= devlink_nl_reload_doit,
-		.post_doit	= devlink_nl_post_doit,
+		.post_doit	= devlink_nl_post_doit_dev_lock,
 		.policy		= devlink_reload_nl_policy,
 		.maxattr	= DEVLINK_ATTR_RELOAD_LIMITS,
 		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
net/devlink/netlink_gen.h +5 -0
index 0e9e89c31c31..02f3c0bfae0e 100644
@@ -22,12 +22,17 @@ int devlink_nl_pre_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
 			struct genl_info *info);
 int devlink_nl_pre_doit_port(const struct genl_split_ops *ops,
 			     struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_pre_doit_dev_lock(const struct genl_split_ops *ops,
+				 struct sk_buff *skb, struct genl_info *info);
 int devlink_nl_pre_doit_port_optional(const struct genl_split_ops *ops,
 				      struct sk_buff *skb,
 				      struct genl_info *info);
 void
 devlink_nl_post_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
 		     struct genl_info *info);
+void
+devlink_nl_post_doit_dev_lock(const struct genl_split_ops *ops,
+			      struct sk_buff *skb, struct genl_info *info);
 
 int devlink_nl_get_doit(struct sk_buff *skb, struct genl_info *info);
 int devlink_nl_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 5/14
#10 lore raw

Re: [PATCH net-next 05/14] devlink: Acquire device lock during reload command

Quoted 29 lines · Petr Machata

From: Ido Schimmel <[email protected]>

Device drivers register with devlink from their probe routines (under the device lock) by acquiring the devlink instance lock and calling devl_register().

Drivers that support a devlink reload usually implement the reload_{down, up}() operations in a similar fashion to their remove and probe routines, respectively.

However, while the remove and probe routines are invoked with the device lock held, the reload operations are only invoked with the devlink instance lock held. It is therefore impossible for drivers to acquire the device lock from their reload operations, as this would result in lock inversion.

The motivating use case for invoking the reload operations with the device lock held is in mlxsw which needs to trigger a PCI reset as part of the reload. The driver cannot call pci_reset_function() as this function acquires the device lock. Instead, it needs to call __pci_reset_function_locked which expects the device lock to be held.

To that end, adjust devlink to always acquire the device lock before the devlink instance lock when performing a reload.

Do that when reload is explicitly triggered by user space by specifying the 'DEVLINK_NL_FLAG_NEED_DEV_LOCK' flag in the pre_doit and post_doit operations of the reload command.

Quoted 6 lines

A previous patch already handled the case where reload is invoked as part of netns dismantle.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#11 lore raw

PATCH 6/14 devlink: Add device lock assert in reload operation

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

Add an assert to verify that the device lock is always held throughout reload operations.

Tested the following flows with netdevsim and mlxsw while lockdep is enabled:

netdevsim:

 # echo "10 1" > /sys/bus/netdevsim/new_device
 # devlink dev reload netdevsim/netdevsim10
 # ip netns add bla
 # devlink dev reload netdevsim/netdevsim10 netns bla
 # ip netns del bla
 # echo 10 > /sys/bus/netdevsim/del_device

mlxsw:

 # devlink dev reload pci/0000:01:00.0
 # ip netns add bla
 # devlink dev reload pci/0000:01:00.0 netns bla
 # ip netns del bla
 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/remove
 # echo 1 > /sys/bus/pci/rescan
Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 net/devlink/dev.c | 8 ++++++++
 1 file changed, 8 insertions(+)
net/devlink/dev.c +8 -0
index 4fc7adb32663..ea6a92f2e6a2 100644
@@ -4,6 +4,7 @@
  * Copyright (c) 2016 Jiri Pirko <[email protected]>
  */
 
+#include <linux/device.h>
 #include <net/genetlink.h>
 #include <net/sock.h>
 #include "devl_internal.h"

@@ -433,6 +434,13 @@ int devlink_reload(struct devlink *devlink, struct net *dest_net,
 	struct net *curr_net;
 	int err;
 
+	/* Make sure the reload operations are invoked with the device lock
+	 * held to allow drivers to trigger functionality that expects it
+	 * (e.g., PCI reset) and to close possible races between these
+	 * operations and probe/remove.
+	 */
+	device_lock_assert(devlink->dev);
+
 	memcpy(remote_reload_stats, devlink->stats.remote_reload_stats,
 	       sizeof(remote_reload_stats));
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 6/14
#12 lore raw

Re: [PATCH net-next 06/14] devlink: Add device lock assert in reload operation

Quoted 26 lines · Petr Machata

From: Ido Schimmel <[email protected]>

Add an assert to verify that the device lock is always held throughout reload operations.

Tested the following flows with netdevsim and mlxsw while lockdep is enabled:

netdevsim:

 # echo "10 1" > /sys/bus/netdevsim/new_device
 # devlink dev reload netdevsim/netdevsim10
 # ip netns add bla
 # devlink dev reload netdevsim/netdevsim10 netns bla
 # ip netns del bla
 # echo 10 > /sys/bus/netdevsim/del_device

mlxsw:

 # devlink dev reload pci/0000:01:00.0
 # ip netns add bla
 # devlink dev reload pci/0000:01:00.0 netns bla
 # ip netns del bla
 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/remove
 # echo 1 > /sys/bus/pci/rescan
Quoted 3 lines
Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Jiri Pirko <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#13 lore raw

PATCH 7/14 PCI: Add no PM reset quirk for NVIDIA Spectrum devices

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

Spectrum-{1,2,3,4} devices report that a D3hot->D0 transition causes a reset (i.e., they advertise NoSoftRst-). However, this transition does not have any effect on the device: It continues to be operational and network ports remain up. Advertising this support makes it seem as if a PM reset is viable for these devices. Mark it as unavailable to skip it when testing reset methods.

Before:

 # cat /sys/bus/pci/devices/0000\:03\:00.0/reset_method
 pm bus

After:

 # cat /sys/bus/pci/devices/0000\:03\:00.0/reset_method
 bus
Signed-off-by Ido Schimmel <[email protected]>
Acked-by Bjorn Helgaas <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 drivers/pci/quirks.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)
drivers/pci/quirks.c +13 -0
index ea476252280a..d208047d1b8f 100644
@@ -3786,6 +3786,19 @@ static void quirk_no_pm_reset(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_VENDOR_ID_ATI, PCI_ANY_ID,
 			       PCI_CLASS_DISPLAY_VGA, 8, quirk_no_pm_reset);
 
+/*
+ * Spectrum-{1,2,3,4} devices report that a D3hot->D0 transition causes a reset
+ * (i.e., they advertise NoSoftRst-). However, this transition does not have
+ * any effect on the device: It continues to be operational and network ports
+ * remain up. Advertising this support makes it seem as if a PM reset is viable
+ * for these devices. Mark it as unavailable to skip it when testing reset
+ * methods.
+ */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcb84, quirk_no_pm_reset);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcf6c, quirk_no_pm_reset);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcf70, quirk_no_pm_reset);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcf80, quirk_no_pm_reset);
+
 /*
  * Thunderbolt controllers with broken MSI hotplug signaling:
  * Entire 1st generation (Light Ridge, Eagle Ridge, Light Peak) and part
Signature · 1 line
2.41.0
reviewer
#14 lore raw

Re: [PATCH net-next 07/14] PCI: Add no PM reset quirk for NVIDIA Spectrum devices

+ [email protected]

Quoted 14 lines · Petr Machata

From: Ido Schimmel <[email protected]>

Spectrum-{1,2,3,4} devices report that a D3hot->D0 transition causes a reset (i.e., they advertise NoSoftRst-). However, this transition does not have any effect on the device: It continues to be operational and network ports remain up. Advertising this support makes it seem as if a PM reset is viable for these devices. Mark it as unavailable to skip it when testing reset methods.

Before:

 # cat /sys/bus/pci/devices/0000\:03\:00.0/reset_method
 pm bus
Quoted 8 lines

After:

 # cat /sys/bus/pci/devices/0000\:03\:00.0/reset_method
 bus
Signed-off-by Ido Schimmel <[email protected]>
Acked-by Bjorn Helgaas <[email protected]>
Signed-off-by Petr Machata <[email protected]>

Thanks,

my understanding is that this matches the use-case for which quirk_no_pm_reset was introduced.

Quoted 31 lines
---
 drivers/pci/quirks.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)
drivers/pci/quirks.c +13 -0
index ea476252280a..d208047d1b8f 100644
@@ -3786,6 +3786,19 @@ static void quirk_no_pm_reset(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_VENDOR_ID_ATI, PCI_ANY_ID,
 			       PCI_CLASS_DISPLAY_VGA, 8, quirk_no_pm_reset);
 
+/*
+ * Spectrum-{1,2,3,4} devices report that a D3hot->D0 transition causes a reset
+ * (i.e., they advertise NoSoftRst-). However, this transition does not have
+ * any effect on the device: It continues to be operational and network ports
+ * remain up. Advertising this support makes it seem as if a PM reset is viable
+ * for these devices. Mark it as unavailable to skip it when testing reset
+ * methods.
+ */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcb84, quirk_no_pm_reset);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcf6c, quirk_no_pm_reset);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcf70, quirk_no_pm_reset);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, 0xcf80, quirk_no_pm_reset);
+
 /*
  * Thunderbolt controllers with broken MSI hotplug signaling:
  * Entire 1st generation (Light Ridge, Eagle Ridge, Light Peak) and part
Signature · 1 line
2.41.0
author maintainer
#15 lore raw

PATCH 8/14 PCI: Add debug print for device ready delay

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

Currently, the time it took a PCI device to become ready after reset is only printed if it was longer than 1000ms ('PCI_RESET_WAIT'). However, for debugging purposes it is useful to know this time even if it was shorter. For example, with the device I am working on, hardware engineers asked to verify that it becomes ready on the first try (no delay).

To that end, add a debug level print that can be enabled using dynamic debug. Example:

 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
 # dmesg -c | grep ready
 # echo "file drivers/pci/pci.c +p" > /sys/kernel/debug/dynamic_debug/control
 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
 # dmesg -c | grep ready
 [  396.060335] mlxsw_spectrum4 0000:01:00.0: ready 0ms after bus reset
 # echo "file drivers/pci/pci.c -p" > /sys/kernel/debug/dynamic_debug/control
 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
 # dmesg -c | grep ready
Signed-off-by Ido Schimmel <[email protected]>
Acked-by Bjorn Helgaas <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 drivers/pci/pci.c | 3 +++
 1 file changed, 3 insertions(+)
drivers/pci/pci.c +3 -0
index 55bc3576a985..69d20d585f88 100644
@@ -1219,6 +1219,9 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
 	if (delay > PCI_RESET_WAIT)
 		pci_info(dev, "ready %dms after %s\n", delay - 1,
 			 reset_type);
+	else
+		pci_dbg(dev, "ready %dms after %s\n", delay - 1,
+			reset_type);
 
 	return 0;
 }
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 8/14
#16 lore raw

Re: [PATCH net-next 08/14] PCI: Add debug print for device ready delay

+ [email protected]

Quoted 22 lines · Petr Machata

From: Ido Schimmel <[email protected]>

Currently, the time it took a PCI device to become ready after reset is only printed if it was longer than 1000ms ('PCI_RESET_WAIT'). However, for debugging purposes it is useful to know this time even if it was shorter. For example, with the device I am working on, hardware engineers asked to verify that it becomes ready on the first try (no delay).

To that end, add a debug level print that can be enabled using dynamic debug. Example:

 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
 # dmesg -c | grep ready
 # echo "file drivers/pci/pci.c +p" > /sys/kernel/debug/dynamic_debug/control
 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
 # dmesg -c | grep ready
 [  396.060335] mlxsw_spectrum4 0000:01:00.0: ready 0ms after bus reset
 # echo "file drivers/pci/pci.c -p" > /sys/kernel/debug/dynamic_debug/control
 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
 # dmesg -c | grep ready
Quoted 3 lines
Signed-off-by Ido Schimmel <[email protected]>
Acked-by Bjorn Helgaas <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
Quoted 21 lines
---
 drivers/pci/pci.c | 3 +++
 1 file changed, 3 insertions(+)
drivers/pci/pci.c +3 -0
index 55bc3576a985..69d20d585f88 100644
@@ -1219,6 +1219,9 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
 	if (delay > PCI_RESET_WAIT)
 		pci_info(dev, "ready %dms after %s\n", delay - 1,
 			 reset_type);
+	else
+		pci_dbg(dev, "ready %dms after %s\n", delay - 1,
+			reset_type);
 
 	return 0;
 }
Signature · 1 line
2.41.0
author maintainer
#17 lore raw

PATCH 9/14 mlxsw: Extend MRSR pack() function to support new commands

In reply to Petr Machata

From: Amit Cohen <[email protected]>

Currently mlxsw_reg_mrsr_pack() always sets 'command=1'. As preparation for support of new reset flow, pass the command as an argument to the function and add an enum for this field.

For now, always pass 'command=1' to the pack() function.

Signed-off-by Amit Cohen <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 drivers/net/ethernet/mellanox/mlxsw/pci.c |  2 +-
 drivers/net/ethernet/mellanox/mlxsw/reg.h | 14 ++++++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)
drivers/net/ethernet/mellanox/mlxsw/pci.c +1 -1
index e4b25e187467..7af37f78ed1a 100644
@@ -1491,7 +1491,7 @@ static int mlxsw_pci_sw_reset(struct mlxsw_pci *mlxsw_pci,
 		return err;
 	}
 
-	mlxsw_reg_mrsr_pack(mrsr_pl);
+	mlxsw_reg_mrsr_pack(mrsr_pl, MLXSW_REG_MRSR_COMMAND_SOFTWARE_RESET);
 	err = mlxsw_reg_write(mlxsw_pci->core, MLXSW_REG(mrsr), mrsr_pl);
 	if (err)
 		return err;
drivers/net/ethernet/mellanox/mlxsw/reg.h +12 -2
index 25b294fdeb3d..13c0ff994537 100644
@@ -10122,6 +10122,15 @@ mlxsw_reg_mgir_unpack(char *payload, u32 *hw_rev, char *fw_info_psid,
 
 MLXSW_REG_DEFINE(mrsr, MLXSW_REG_MRSR_ID, MLXSW_REG_MRSR_LEN);
 
+enum mlxsw_reg_mrsr_command {
+	/* Switch soft reset, does not reset PCI firmware. */
+	MLXSW_REG_MRSR_COMMAND_SOFTWARE_RESET = 1,
+	/* Reset will be done when PCI link will be disabled.
+	 * This command will reset PCI firmware also.
+	 */
+	MLXSW_REG_MRSR_COMMAND_RESET_AT_PCI_DISABLE = 6,
+};
+
 /* reg_mrsr_command
  * Reset/shutdown command
  * 0 - do nothing

@@ -10130,10 +10139,11 @@ MLXSW_REG_DEFINE(mrsr, MLXSW_REG_MRSR_ID, MLXSW_REG_MRSR_LEN);
  */
 MLXSW_ITEM32(reg, mrsr, command, 0x00, 0, 4);
 
-static inline void mlxsw_reg_mrsr_pack(char *payload)
+static inline void mlxsw_reg_mrsr_pack(char *payload,
+				       enum mlxsw_reg_mrsr_command command)
 {
 	MLXSW_REG_ZERO(mrsr, payload);
-	mlxsw_reg_mrsr_command_set(payload, 1);
+	mlxsw_reg_mrsr_command_set(payload, command);
 }
 
 /* MLCR - Management LED Control Register
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 9/14
#18 lore raw

Re: [PATCH net-next 09/14] mlxsw: Extend MRSR pack() function to support new commands

Quoted 6 lines · Petr Machata

From: Amit Cohen <[email protected]>

Currently mlxsw_reg_mrsr_pack() always sets 'command=1'. As preparation for support of new reset flow, pass the command as an argument to the function and add an enum for this field.

Quoted 6 lines

For now, always pass 'command=1' to the pack() function.

Signed-off-by Amit Cohen <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#19 lore raw

PATCH 10/14 mlxsw: pci: Rename mlxsw_pci_sw_reset()

In reply to Petr Machata

From: Amit Cohen <[email protected]>

In the next patches, mlxsw_pci_sw_reset() will be extended to support more reset types and will not necessarily issue a software reset. Rename the function to reflect that.

Signed-off-by Amit Cohen <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 drivers/net/ethernet/mellanox/mlxsw/pci.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
drivers/net/ethernet/mellanox/mlxsw/pci.c +5 -5
index 7af37f78ed1a..fe0b8a38d44e 100644
@@ -1476,8 +1476,8 @@ static int mlxsw_pci_sys_ready_wait(struct mlxsw_pci *mlxsw_pci,
 	return -EBUSY;
 }
 
-static int mlxsw_pci_sw_reset(struct mlxsw_pci *mlxsw_pci,
-			      const struct pci_device_id *id)
+static int
+mlxsw_pci_reset(struct mlxsw_pci *mlxsw_pci, const struct pci_device_id *id)
 {
 	struct pci_dev *pdev = mlxsw_pci->pdev;
 	char mrsr_pl[MLXSW_REG_MRSR_LEN];

@@ -1537,9 +1537,9 @@ static int mlxsw_pci_init(void *bus_priv, struct mlxsw_core *mlxsw_core,
 	if (!mbox)
 		return -ENOMEM;
 
-	err = mlxsw_pci_sw_reset(mlxsw_pci, mlxsw_pci->id);
+	err = mlxsw_pci_reset(mlxsw_pci, mlxsw_pci->id);
 	if (err)
-		goto err_sw_reset;
+		goto err_reset;
 
 	err = mlxsw_pci_alloc_irq_vectors(mlxsw_pci);
 	if (err < 0) {

@@ -1672,7 +1672,7 @@ static int mlxsw_pci_init(void *bus_priv, struct mlxsw_core *mlxsw_core,
 err_query_fw:
 	mlxsw_pci_free_irq_vectors(mlxsw_pci);
 err_alloc_irq:
-err_sw_reset:
+err_reset:
 mbox_put:
 	mlxsw_cmd_mbox_free(mbox);
 	return err;
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 10/14
#20 lore raw

Re: [PATCH net-next 10/14] mlxsw: pci: Rename mlxsw_pci_sw_reset()

Quoted 10 lines · Petr Machata

From: Amit Cohen <[email protected]>

In the next patches, mlxsw_pci_sw_reset() will be extended to support more reset types and will not necessarily issue a software reset. Rename the function to reflect that.

Signed-off-by Amit Cohen <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#21 lore raw

PATCH 11/14 mlxsw: pci: Move software reset code to a separate function

In reply to Petr Machata

From: Amit Cohen <[email protected]>

In general, the existing flow of software reset in the driver is:
1. Wait for system ready status.
2. Send MRSR command, to start the reset.
3. Wait for system ready status.

This flow will be extended once a new reset command is supported. As a preparation, move step #2 to a separate function.

Signed-off-by Amit Cohen <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 drivers/net/ethernet/mellanox/mlxsw/pci.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)
drivers/net/ethernet/mellanox/mlxsw/pci.c +11 -5
index fe0b8a38d44e..080881c94c5a 100644
@@ -1476,11 +1476,18 @@ static int mlxsw_pci_sys_ready_wait(struct mlxsw_pci *mlxsw_pci,
 	return -EBUSY;
 }
 
-static int
-mlxsw_pci_reset(struct mlxsw_pci *mlxsw_pci, const struct pci_device_id *id)
+static int mlxsw_pci_reset_sw(struct mlxsw_pci *mlxsw_pci)
 {
-	struct pci_dev *pdev = mlxsw_pci->pdev;
 	char mrsr_pl[MLXSW_REG_MRSR_LEN];
+
+	mlxsw_reg_mrsr_pack(mrsr_pl, MLXSW_REG_MRSR_COMMAND_SOFTWARE_RESET);
+	return mlxsw_reg_write(mlxsw_pci->core, MLXSW_REG(mrsr), mrsr_pl);
+}
+
+static int
+mlxsw_pci_reset(struct mlxsw_pci *mlxsw_pci, const struct pci_device_id *id)
+{
+	struct pci_dev *pdev = mlxsw_pci->pdev;
 	u32 sys_status;
 	int err;
 

@@ -1491,8 +1498,7 @@ mlxsw_pci_reset(struct mlxsw_pci *mlxsw_pci, const struct pci_device_id *id)
 		return err;
 	}
 
-	mlxsw_reg_mrsr_pack(mrsr_pl, MLXSW_REG_MRSR_COMMAND_SOFTWARE_RESET);
-	err = mlxsw_reg_write(mlxsw_pci->core, MLXSW_REG(mrsr), mrsr_pl);
+	err = mlxsw_pci_reset_sw(mlxsw_pci);
 	if (err)
 		return err;
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 11/14
#22 lore raw

Re: [PATCH net-next 11/14] mlxsw: pci: Move software reset code to a separate function

Quoted 7 lines · Petr Machata

From: Amit Cohen <[email protected]>

In general, the existing flow of software reset in the driver is:
1. Wait for system ready status.
2. Send MRSR command, to start the reset.
3. Wait for system ready status.

Quoted 7 lines

This flow will be extended once a new reset command is supported. As a preparation, move step #2 to a separate function.

Signed-off-by Amit Cohen <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#23 lore raw

PATCH 12/14 mlxsw: pci: Add support for new reset flow

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

The driver resets the device during probe and during a devlink reload. The current reset method reloads the current firmware version or a pending one, if one was previously flashed using devlink. However, the current reset method does not result in a PCI hot reset, preventing the PCI firmware from being upgraded, unless the system is rebooted.

To solve this problem, a new reset command (6) was implemented in the firmware. Unlike the current command (1), after issuing the new command the device will not start the reset immediately, but only after a PCI hot reset.

Implement the new reset method by first verifying that it is supported by the current firmware version by querying the Management Capabilities Mask (MCAM) register. If supported, issue the new reset command (6) via MRSR register followed by a PCI reset by calling __pci_reset_function_locked().

Once the PCI firmware is operational, go back to the regular reset flow and wait for the entire device to become ready. That is, repeatedly read the "system_status" register from the BAR until a value of "FW_READY" (0x5E) appears.

Tested:

 # for i in $(seq 1 10); do devlink dev reload pci/0000:01:00.0; done
Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 drivers/net/ethernet/mellanox/mlxsw/pci.c | 44 ++++++++++++++++++++++-
 drivers/net/ethernet/mellanox/mlxsw/reg.h |  2 ++
 2 files changed, 45 insertions(+), 1 deletion(-)
drivers/net/ethernet/mellanox/mlxsw/pci.c +43 -1
index 080881c94c5a..726ed707e27b 100644
@@ -1476,6 +1476,33 @@ static int mlxsw_pci_sys_ready_wait(struct mlxsw_pci *mlxsw_pci,
 	return -EBUSY;
 }
 
+static int mlxsw_pci_reset_at_pci_disable(struct mlxsw_pci *mlxsw_pci)
+{
+	struct pci_dev *pdev = mlxsw_pci->pdev;
+	char mrsr_pl[MLXSW_REG_MRSR_LEN];
+	int err;
+
+	mlxsw_reg_mrsr_pack(mrsr_pl,
+			    MLXSW_REG_MRSR_COMMAND_RESET_AT_PCI_DISABLE);
+	err = mlxsw_reg_write(mlxsw_pci->core, MLXSW_REG(mrsr), mrsr_pl);
+	if (err)
+		return err;
+
+	device_lock_assert(&pdev->dev);
+
+	pci_cfg_access_lock(pdev);
+	pci_save_state(pdev);
+
+	err = __pci_reset_function_locked(pdev);
+	if (err)
+		pci_err(pdev, "PCI function reset failed with %d\n", err);
+
+	pci_restore_state(pdev);
+	pci_cfg_access_unlock(pdev);
+
+	return err;
+}
+
 static int mlxsw_pci_reset_sw(struct mlxsw_pci *mlxsw_pci)
 {
 	char mrsr_pl[MLXSW_REG_MRSR_LEN];

@@ -1488,6 +1515,8 @@ static int
 mlxsw_pci_reset(struct mlxsw_pci *mlxsw_pci, const struct pci_device_id *id)
 {
 	struct pci_dev *pdev = mlxsw_pci->pdev;
+	char mcam_pl[MLXSW_REG_MCAM_LEN];
+	bool pci_reset_supported;
 	u32 sys_status;
 	int err;
 

@@ -1498,10 +1527,23 @@ mlxsw_pci_reset(struct mlxsw_pci *mlxsw_pci, const struct pci_device_id *id)
 		return err;
 	}
 
-	err = mlxsw_pci_reset_sw(mlxsw_pci);
+	mlxsw_reg_mcam_pack(mcam_pl,
+			    MLXSW_REG_MCAM_FEATURE_GROUP_ENHANCED_FEATURES);
+	err = mlxsw_reg_query(mlxsw_pci->core, MLXSW_REG(mcam), mcam_pl);
 	if (err)
 		return err;
 
+	mlxsw_reg_mcam_unpack(mcam_pl, MLXSW_REG_MCAM_PCI_RESET,
+			      &pci_reset_supported);
+
+	if (pci_reset_supported) {
+		pci_dbg(pdev, "Starting PCI reset flow\n");
+		err = mlxsw_pci_reset_at_pci_disable(mlxsw_pci);
+	} else {
+		pci_dbg(pdev, "Starting software reset flow\n");
+		err = mlxsw_pci_reset_sw(mlxsw_pci);
+	}
+
 	err = mlxsw_pci_sys_ready_wait(mlxsw_pci, id, &sys_status);
 	if (err) {
 		dev_err(&pdev->dev, "Failed to reach system ready status after reset. Status is 0x%x\n",
drivers/net/ethernet/mellanox/mlxsw/reg.h +2 -0
index 13c0ff994537..e26e9d06bd72 100644
@@ -10594,6 +10594,8 @@ MLXSW_ITEM32(reg, mcam, feature_group, 0x00, 16, 8);
 enum mlxsw_reg_mcam_mng_feature_cap_mask_bits {
 	/* If set, MCIA supports 128 bytes payloads. Otherwise, 48 bytes. */
 	MLXSW_REG_MCAM_MCIA_128B = 34,
+	/* If set, MRSR.command=6 is supported. */
+	MLXSW_REG_MCAM_PCI_RESET = 48,
 };
 
 #define MLXSW_REG_BYTES_PER_DWORD 0x4
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 12/14
#24 lore raw

Re: [PATCH net-next 12/14] mlxsw: pci: Add support for new reset flow

Quoted 24 lines · Petr Machata

From: Ido Schimmel <[email protected]>

The driver resets the device during probe and during a devlink reload. The current reset method reloads the current firmware version or a pending one, if one was previously flashed using devlink. However, the current reset method does not result in a PCI hot reset, preventing the PCI firmware from being upgraded, unless the system is rebooted.

To solve this problem, a new reset command (6) was implemented in the firmware. Unlike the current command (1), after issuing the new command the device will not start the reset immediately, but only after a PCI hot reset.

Implement the new reset method by first verifying that it is supported by the current firmware version by querying the Management Capabilities Mask (MCAM) register. If supported, issue the new reset command (6) via MRSR register followed by a PCI reset by calling __pci_reset_function_locked().

Once the PCI firmware is operational, go back to the regular reset flow and wait for the entire device to become ready. That is, repeatedly read the "system_status" register from the BAR until a value of "FW_READY" (0x5E) appears.

Quoted 7 lines

Tested:

 # for i in $(seq 1 10); do devlink dev reload pci/0000:01:00.0; done
Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#25 lore raw

PATCH 13/14 mlxsw: pci: Implement PCI reset handlers

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

Implement reset_prepare() and reset_done() handlers that are invoked by the PCI core before and after issuing a PCI reset, respectively.

Specifically, implement reset_prepare() by calling mlxsw_core_bus_device_unregister() and reset_done() by calling mlxsw_core_bus_device_register(). This is the same implementation as the reload_{down,up}() devlink operations with the following differences:

1. The devlink instance is unregistered and then registered again after the reset.

2. A reset via the device's command interface (using MRSR register) is not issued during reset_done() as PCI core already issued a PCI reset.

Tested:

 # for i in $(seq 1 10); do echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset; done
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 drivers/net/ethernet/mellanox/mlxsw/pci.c | 28 +++++++++++++++++++++++
 1 file changed, 28 insertions(+)
drivers/net/ethernet/mellanox/mlxsw/pci.c +28 -0
index 726ed707e27b..5b1f2483a3cc 100644
@@ -130,6 +130,7 @@ struct mlxsw_pci {
 	const struct pci_device_id *id;
 	enum mlxsw_pci_cqe_v max_cqe_ver; /* Maximal supported CQE version */
 	u8 num_sdq_cqs; /* Number of CQs used for SDQs */
+	bool skip_reset;
 };
 
 static void mlxsw_pci_queue_tasklet_schedule(struct mlxsw_pci_queue *q)

@@ -1527,6 +1528,10 @@ mlxsw_pci_reset(struct mlxsw_pci *mlxsw_pci, const struct pci_device_id *id)
 		return err;
 	}
 
+	/* PCI core already issued a PCI reset, do not issue another reset. */
+	if (mlxsw_pci->skip_reset)
+		return 0;
+
 	mlxsw_reg_mcam_pack(mcam_pl,
 			    MLXSW_REG_MCAM_FEATURE_GROUP_ENHANCED_FEATURES);
 	err = mlxsw_reg_query(mlxsw_pci->core, MLXSW_REG(mcam), mcam_pl);

@@ -2107,11 +2112,34 @@ static void mlxsw_pci_remove(struct pci_dev *pdev)
 	kfree(mlxsw_pci);
 }
 
+static void mlxsw_pci_reset_prepare(struct pci_dev *pdev)
+{
+	struct mlxsw_pci *mlxsw_pci = pci_get_drvdata(pdev);
+
+	mlxsw_core_bus_device_unregister(mlxsw_pci->core, false);
+}
+
+static void mlxsw_pci_reset_done(struct pci_dev *pdev)
+{
+	struct mlxsw_pci *mlxsw_pci = pci_get_drvdata(pdev);
+
+	mlxsw_pci->skip_reset = true;
+	mlxsw_core_bus_device_register(&mlxsw_pci->bus_info, &mlxsw_pci_bus,
+				       mlxsw_pci, false, NULL, NULL);
+	mlxsw_pci->skip_reset = false;
+}
+
+static const struct pci_error_handlers mlxsw_pci_err_handler = {
+	.reset_prepare = mlxsw_pci_reset_prepare,
+	.reset_done = mlxsw_pci_reset_done,
+};
+
 int mlxsw_pci_driver_register(struct pci_driver *pci_driver)
 {
 	pci_driver->probe = mlxsw_pci_probe;
 	pci_driver->remove = mlxsw_pci_remove;
 	pci_driver->shutdown = mlxsw_pci_remove;
+	pci_driver->err_handler = &mlxsw_pci_err_handler;
 	return pci_register_driver(pci_driver);
 }
 EXPORT_SYMBOL(mlxsw_pci_driver_register);
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 13/14
#26 lore raw

Re: [PATCH net-next 13/14] mlxsw: pci: Implement PCI reset handlers

Quoted 17 lines · Petr Machata

From: Ido Schimmel <[email protected]>

Implement reset_prepare() and reset_done() handlers that are invoked by the PCI core before and after issuing a PCI reset, respectively.

Specifically, implement reset_prepare() by calling mlxsw_core_bus_device_unregister() and reset_done() by calling mlxsw_core_bus_device_register(). This is the same implementation as the reload_{down,up}() devlink operations with the following differences:

1. The devlink instance is unregistered and then registered again after the reset.

2. A reset via the device's command interface (using MRSR register) is not issued during reset_done() as PCI core already issued a PCI reset.

Quoted 7 lines

Tested:

 # for i in $(seq 1 10); do echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset; done
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Ido Schimmel <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
author maintainer
#27 lore raw

PATCH 14/14 selftests: mlxsw: Add PCI reset test

In reply to Petr Machata

From: Ido Schimmel <[email protected]>

Test that PCI reset works correctly by verifying that only the expected reset methods are supported and that after issuing the reset the ifindex of the port changes.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Petr Machata <[email protected]>
---
 .../selftests/drivers/net/mlxsw/pci_reset.sh  | 58 +++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100755 tools/testing/selftests/drivers/net/mlxsw/pci_reset.sh
tools/testing/selftests/drivers/net/mlxsw/pci_reset.sh new file +58 -0
new file mode 100755
index 000000000000..fe0343b95e6c
@@ -0,0 +1,58 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Test that PCI reset works correctly by verifying that only the expected reset
+# methods are supported and that after issuing the reset the ifindex of the
+# port changes.
+
+lib_dir=$(dirname $0)/../../../net/forwarding
+
+ALL_TESTS="
+	pci_reset_test
+"
+NUM_NETIFS=1
+source $lib_dir/lib.sh
+source $lib_dir/devlink_lib.sh
+
+pci_reset_test()
+{
+	RET=0
+
+	local bus=$(echo $DEVLINK_DEV | cut -d '/' -f 1)
+	local bdf=$(echo $DEVLINK_DEV | cut -d '/' -f 2)
+
+	if [ $bus != "pci" ]; then
+		check_err 1 "devlink device is not a PCI device"
+		log_test "pci reset"
+		return
+	fi
+
+	if [ ! -f /sys/bus/pci/devices/$bdf/reset_method ]; then
+		check_err 1 "reset is not supported"
+		log_test "pci reset"
+		return
+	fi
+
+	[[ $(cat /sys/bus/pci/devices/$bdf/reset_method) == "bus" ]]
+	check_err $? "only \"bus\" reset method should be supported"
+
+	local ifindex_pre=$(ip -j link show dev $swp1 | jq '.[]["ifindex"]')
+
+	echo 1 > /sys/bus/pci/devices/$bdf/reset
+	check_err $? "reset failed"
+
+	# Wait for udev to rename newly created netdev.
+	udevadm settle
+
+	local ifindex_post=$(ip -j link show dev $swp1 | jq '.[]["ifindex"]')
+
+	[[ $ifindex_pre != $ifindex_post ]]
+	check_err $? "reset not performed"
+
+	log_test "pci reset"
+}
+
+swp1=${NETIFS[p1]}
+tests_run
+
+exit $EXIT_STATUS
Signature · 1 line
2.41.0
reviewer Reviewed-by on v1 14/14
#28 lore raw

Re: [PATCH net-next 14/14] selftests: mlxsw: Add PCI reset test

+ linux-kselftest ML, Shuah Khan

Quoted 9 lines · Petr Machata

From: Ido Schimmel <[email protected]>

Test that PCI reset works correctly by verifying that only the expected reset methods are supported and that after issuing the reset the ifindex of the port changes.

Signed-off-by Ido Schimmel <[email protected]>
Reviewed-by Petr Machata <[email protected]>
Signed-off-by Petr Machata <[email protected]>
Reviewed-by Simon Horman <[email protected]>
Quoted 72 lines
---
 .../selftests/drivers/net/mlxsw/pci_reset.sh  | 58 +++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100755 tools/testing/selftests/drivers/net/mlxsw/pci_reset.sh
tools/testing/selftests/drivers/net/mlxsw/pci_reset.sh new file +58 -0
new file mode 100755
index 000000000000..fe0343b95e6c
@@ -0,0 +1,58 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Test that PCI reset works correctly by verifying that only the expected reset
+# methods are supported and that after issuing the reset the ifindex of the
+# port changes.
+
+lib_dir=$(dirname $0)/../../../net/forwarding
+
+ALL_TESTS="
+	pci_reset_test
+"
+NUM_NETIFS=1
+source $lib_dir/lib.sh
+source $lib_dir/devlink_lib.sh
+
+pci_reset_test()
+{
+	RET=0
+
+	local bus=$(echo $DEVLINK_DEV | cut -d '/' -f 1)
+	local bdf=$(echo $DEVLINK_DEV | cut -d '/' -f 2)
+
+	if [ $bus != "pci" ]; then
+		check_err 1 "devlink device is not a PCI device"
+		log_test "pci reset"
+		return
+	fi
+
+	if [ ! -f /sys/bus/pci/devices/$bdf/reset_method ]; then
+		check_err 1 "reset is not supported"
+		log_test "pci reset"
+		return
+	fi
+
+	[[ $(cat /sys/bus/pci/devices/$bdf/reset_method) == "bus" ]]
+	check_err $? "only \"bus\" reset method should be supported"
+
+	local ifindex_pre=$(ip -j link show dev $swp1 | jq '.[]["ifindex"]')
+
+	echo 1 > /sys/bus/pci/devices/$bdf/reset
+	check_err $? "reset failed"
+
+	# Wait for udev to rename newly created netdev.
+	udevadm settle
+
+	local ifindex_post=$(ip -j link show dev $swp1 | jq '.[]["ifindex"]')
+
+	[[ $ifindex_pre != $ifindex_post ]]
+	check_err $? "reset not performed"
+
+	log_test "pci reset"
+}
+
+swp1=${NETIFS[p1]}
+tests_run
+
+exit $EXIT_STATUS
Signature · 1 line
2.41.0
CI
#29 lore raw
In reply to Petr Machata
This series was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:

Hello:

This series was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:

Quoted 11 lines · On Wed, 15 Nov 2023 13:17:09 +0100 you wrote:

Ido Schimmel writes:

This patchset changes mlxsw to issue a PCI reset during probe and devlink reload so that the PCI firmware could be upgraded without a reboot.

Unlike the old version of this patchset [1], in this version the driver no longer tries to issue a PCI reset by triggering a PCI link toggle on its own, but instead calls the PCI core to issue the reset.

[...]

Here is the summary with links:
- [net-next,01/14] devlink: Move private netlink flags to C file

    https://git.kernel.org/netdev/net-next/c/526dd6d7877b
  - [net-next,02/14] devlink: Acquire device lock during netns dismantle
    https://git.kernel.org/netdev/net-next/c/e21c52d7814f
  - [net-next,03/14] devlink: Enable the use of private flags in post_doit operations
    (no matching commit)
  - [net-next,04/14] devlink: Allow taking device lock in pre_doit operations
    https://git.kernel.org/netdev/net-next/c/d32c38256db3
  - [net-next,05/14] devlink: Acquire device lock during reload command
    https://git.kernel.org/netdev/net-next/c/bf6b200bc80d
  - [net-next,06/14] devlink: Add device lock assert in reload operation
    https://git.kernel.org/netdev/net-next/c/527a07e176ea
  - [net-next,07/14] PCI: Add no PM reset quirk for NVIDIA Spectrum devices
    https://git.kernel.org/netdev/net-next/c/3ed48c80b28d
  - [net-next,08/14] PCI: Add debug print for device ready delay
    https://git.kernel.org/netdev/net-next/c/0a5ef95923e0
  - [net-next,09/14] mlxsw: Extend MRSR pack() function to support new commands
    https://git.kernel.org/netdev/net-next/c/e6dbab40fa09
  - [net-next,10/14] mlxsw: pci: Rename mlxsw_pci_sw_reset()
    https://git.kernel.org/netdev/net-next/c/bdf85f3a695f
  - [net-next,11/14] mlxsw: pci: Move software reset code to a separate function
    (no matching commit)
  - [net-next,12/14] mlxsw: pci: Add support for new reset flow
    https://git.kernel.org/netdev/net-next/c/f257c73e5356
  - [net-next,13/14] mlxsw: pci: Implement PCI reset handlers
    https://git.kernel.org/netdev/net-next/c/5e12d0898583
  - [net-next,14/14] selftests: mlxsw: Add PCI reset test
    https://git.kernel.org/netdev/net-next/c/af51d6bd0b13

You are awesome, thank you!

Signature · 2 lines
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