Patch "net/mlx5: Nack sync reset request when HotPlug is enabled" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    net/mlx5: Nack sync reset request when HotPlug is enabled

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-mlx5-nack-sync-reset-request-when-hotplug-is-ena.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit fabdb2abbb4c7d9a92c80d62340aa1aa66b3425f
Author: Moshe Shemesh <moshe@xxxxxxxxxx>
Date:   Mon Aug 7 13:11:32 2023 +0300

    net/mlx5: Nack sync reset request when HotPlug is enabled
    
    [ Upstream commit 3d7a3f2612d75de5f371a681038b089ded6667eb ]
    
    Current sync reset flow is not supported when PCIe bridge connected
    directly to mlx5 device has HotPlug interrupt enabled and can be
    triggered on link state change event. Return nack on reset request in
    such case.
    
    Fixes: 92501fa6e421 ("net/mlx5: Ack on sync_reset_request only if PF can do reset_now")
    Signed-off-by: Moshe Shemesh <moshe@xxxxxxxxxx>
    Reviewed-by: Shay Drory <shayd@xxxxxxxxxx>
    Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
index b568988e92e3e..c4e19d627da21 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
@@ -325,6 +325,29 @@ static void mlx5_fw_live_patch_event(struct work_struct *work)
 		mlx5_core_err(dev, "Failed to reload FW tracer\n");
 }
 
+#if IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE)
+static int mlx5_check_hotplug_interrupt(struct mlx5_core_dev *dev)
+{
+	struct pci_dev *bridge = dev->pdev->bus->self;
+	u16 reg16;
+	int err;
+
+	if (!bridge)
+		return -EOPNOTSUPP;
+
+	err = pcie_capability_read_word(bridge, PCI_EXP_SLTCTL, &reg16);
+	if (err)
+		return err;
+
+	if ((reg16 & PCI_EXP_SLTCTL_HPIE) && (reg16 & PCI_EXP_SLTCTL_DLLSCE)) {
+		mlx5_core_warn(dev, "FW reset is not supported as HotPlug is enabled\n");
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+#endif
+
 static int mlx5_check_dev_ids(struct mlx5_core_dev *dev, u16 dev_id)
 {
 	struct pci_bus *bridge_bus = dev->pdev->bus;
@@ -357,6 +380,12 @@ static bool mlx5_is_reset_now_capable(struct mlx5_core_dev *dev)
 		return false;
 	}
 
+#if IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE)
+	err = mlx5_check_hotplug_interrupt(dev);
+	if (err)
+		return false;
+#endif
+
 	err = pci_read_config_word(dev->pdev, PCI_DEVICE_ID, &dev_id);
 	if (err)
 		return false;