i40e: Check if the BAR size is large enough before writing to registers

This patch fixes the problem with a kernel panic occurring when trying
to bind the i40e driver to a non-i40e port. The problem is fixed by
checking if the BAR size in the device is large enough by reading the
highest register.
Signed-off-by: Adam Ludkiewicz <adam.ludkiewicz@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -14205,7 +14205,17 @@ static int i40e_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	pf->ioremap_len = min_t(int, pci_resource_len(pdev, 0),
 				I40E_MAX_CSR_SPACE);
-
+	/* We believe that the highest register to read is
+	 * I40E_GLGEN_STAT_CLEAR, so we check if the BAR size
+	 * is not less than that before mapping to prevent a
+	 * kernel panic.
+	 */
+	if (pf->ioremap_len < I40E_GLGEN_STAT_CLEAR) {
+		dev_err(&pdev->dev, "Cannot map registers, bar size 0x%X too small, aborting\n",
+			pf->ioremap_len);
+		err = -ENOMEM;
+		goto err_ioremap;
+	}
 	hw->hw_addr = ioremap(pci_resource_start(pdev, 0), pf->ioremap_len);
 	if (!hw->hw_addr) {
 		err = -EIO;