RDMA/efa: Fail probe on missing BARs

In case any of PCI BARs is missing during device probe we would like to
fail as early as possible. Fail if any of the required BARs isn't listed
as a memory BAR.
Reviewed-by: Daniel Kranzdorf <dkkranzd@amazon.com>
Reviewed-by: Firas Jahjah <firasj@amazon.com>
Signed-off-by: Michael Margolin <mrgolin@amazon.com>
Link: https://lore.kernel.org/r/20240513081019.26998-1-mrgolin@amazon.comReviewed-by: Gal Pressman <gal.pressman@linux.dev>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/efa/efa_main.c

@@ -190,15 +190,23 @@ static int efa_request_doorbell_bar(struct efa_dev *dev)
 {
 	u8 db_bar_idx = dev->dev_attr.db_bar;
 	struct pci_dev *pdev = dev->pdev;
-	int bars;
+	int pci_mem_bars;
+	int db_bar;
 	int err;
 
-	if (!(BIT(db_bar_idx) & EFA_BASE_BAR_MASK)) {
-		bars = pci_select_bars(pdev, IORESOURCE_MEM) & BIT(db_bar_idx);
+	db_bar = BIT(db_bar_idx);
+	if (!(db_bar & EFA_BASE_BAR_MASK)) {
+		pci_mem_bars = pci_select_bars(pdev, IORESOURCE_MEM);
+		if (db_bar & ~pci_mem_bars) {
+			dev_err(&pdev->dev,
+				"Doorbells BAR unavailable. Requested %#x, available %#x\n",
+				db_bar, pci_mem_bars);
+			return -ENODEV;
+		}
 
-		err = pci_request_selected_regions(pdev, bars, DRV_MODULE_NAME);
+		err = pci_request_selected_regions(pdev, db_bar, DRV_MODULE_NAME);
 		if (err) {
-			dev_err(&dev->pdev->dev,
+			dev_err(&pdev->dev,
 				"pci_request_selected_regions for bar %d failed %d\n",
 				db_bar_idx, err);
 			return err;
@@ -531,7 +539,7 @@ static struct efa_dev *efa_probe_device(struct pci_dev *pdev)
 {
 	struct efa_com_dev *edev;
 	struct efa_dev *dev;
-	int bars;
+	int pci_mem_bars;
 	int err;
 
 	err = pci_enable_device_mem(pdev);
@@ -556,8 +564,14 @@ static struct efa_dev *efa_probe_device(struct pci_dev *pdev)
 	dev->pdev = pdev;
 	xa_init(&dev->cqs_xa);
 
-	bars = pci_select_bars(pdev, IORESOURCE_MEM) & EFA_BASE_BAR_MASK;
-	err = pci_request_selected_regions(pdev, bars, DRV_MODULE_NAME);
+	pci_mem_bars = pci_select_bars(pdev, IORESOURCE_MEM);
+	if (EFA_BASE_BAR_MASK & ~pci_mem_bars) {
+		dev_err(&pdev->dev, "BARs unavailable. Requested %#x, available %#x\n",
+			(int)EFA_BASE_BAR_MASK, pci_mem_bars);
+		err = -ENODEV;
+		goto err_ibdev_destroy;
+	}
+	err = pci_request_selected_regions(pdev, EFA_BASE_BAR_MASK, DRV_MODULE_NAME);
 	if (err) {
 		dev_err(&pdev->dev, "pci_request_selected_regions failed %d\n",
 			err);