net: libwx: restrict change user-set RSS configuration

Enable/disable SR-IOV will change the number of rings, thereby changing
the RSS configuration that the user has set.

So reject these attempts if netif_is_rxfh_configured() returns true. And
remind the user to reset the RSS configuration.

Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Link: https://patch.msgid.link/20250926023843.34340-5-jiawenwu@trustnetic.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Jiawen Wu

drivers/net/ethernet/wangxun/libwx/wx_hw.c

@@ -2047,28 +2047,30 @@ void wx_store_rsskey(struct wx *wx)
 
 static void wx_setup_reta(struct wx *wx)
 {
-	u16 rss_i = wx->ring_feature[RING_F_RSS].indices;
-	u32 reta_entries = wx_rss_indir_tbl_entries(wx);
-	u32 i, j;
-
-	if (test_bit(WX_FLAG_SRIOV_ENABLED, wx->flags)) {
-		if (test_bit(WX_FLAG_MULTI_64_FUNC, wx->flags))
-			rss_i = rss_i < 2 ? 2 : rss_i;
-		else
-			rss_i = 1;
-	}
-
 	/* Fill out hash function seeds */
 	wx_store_rsskey(wx);
 
 	/* Fill out redirection table */
-	memset(wx->rss_indir_tbl, 0, sizeof(wx->rss_indir_tbl));
+	if (!netif_is_rxfh_configured(wx->netdev)) {
+		u16 rss_i = wx->ring_feature[RING_F_RSS].indices;
+		u32 reta_entries = wx_rss_indir_tbl_entries(wx);
+		u32 i, j;
 
-	for (i = 0, j = 0; i < reta_entries; i++, j++) {
-		if (j == rss_i)
-			j = 0;
+		memset(wx->rss_indir_tbl, 0, sizeof(wx->rss_indir_tbl));
 
-		wx->rss_indir_tbl[i] = j;
+		if (test_bit(WX_FLAG_SRIOV_ENABLED, wx->flags)) {
+			if (test_bit(WX_FLAG_MULTI_64_FUNC, wx->flags))
+				rss_i = rss_i < 2 ? 2 : rss_i;
+			else
+				rss_i = 1;
+		}
+
+		for (i = 0, j = 0; i < reta_entries; i++, j++) {
+			if (j == rss_i)
+				j = 0;
+
+			wx->rss_indir_tbl[i] = j;
+		}
 	}
 
 	wx_store_reta(wx);
@@ -2151,8 +2153,6 @@ static void wx_setup_mrqc(struct wx *wx)
 	/* Disable indicating checksum in descriptor, enables RSS hash */
 	wr32m(wx, WX_PSR_CTL, WX_PSR_CTL_PCSD, WX_PSR_CTL_PCSD);
 
-	netdev_rss_key_fill(wx->rss_key, sizeof(wx->rss_key));
-
 	wx_config_rss_field(wx);
 	wx_enable_rss(wx, wx->rss_enabled);
 	wx_setup_reta(wx);

drivers/net/ethernet/wangxun/libwx/wx_sriov.c

@@ -150,6 +150,12 @@ static int wx_pci_sriov_enable(struct pci_dev *dev,
 	struct wx *wx = pci_get_drvdata(dev);
 	int err = 0, i;
 
+	if (netif_is_rxfh_configured(wx->netdev)) {
+		wx_err(wx, "Cannot enable SR-IOV while RXFH is configured\n");
+		wx_err(wx, "Run 'ethtool -X <if> default' to reset RSS table\n");
+		return -EBUSY;
+	}
+
 	err = __wx_enable_sriov(wx, num_vfs);
 	if (err)
 		return err;
@@ -173,12 +179,20 @@ static int wx_pci_sriov_enable(struct pci_dev *dev,
 	return err;
 }
 
-static void wx_pci_sriov_disable(struct pci_dev *dev)
+static int wx_pci_sriov_disable(struct pci_dev *dev)
 {
 	struct wx *wx = pci_get_drvdata(dev);
 
+	if (netif_is_rxfh_configured(wx->netdev)) {
+		wx_err(wx, "Cannot disable SR-IOV while RXFH is configured\n");
+		wx_err(wx, "Run 'ethtool -X <if> default' to reset RSS table\n");
+		return -EBUSY;
+	}
+
 	wx_disable_sriov(wx);
 	wx_sriov_reinit(wx);
+
+	return 0;
 }
 
 int wx_pci_sriov_configure(struct pci_dev *pdev, int num_vfs)
@@ -187,10 +201,8 @@ int wx_pci_sriov_configure(struct pci_dev *pdev, int num_vfs)
 	int err;
 
 	if (!num_vfs) {
-		if (!pci_vfs_assigned(pdev)) {
-			wx_pci_sriov_disable(pdev);
-			return 0;
-		}
+		if (!pci_vfs_assigned(pdev))
+			return wx_pci_sriov_disable(pdev);
 
 		wx_err(wx, "can't free VFs because some are assigned to VMs.\n");
 		return -EBUSY;