net: ena: disable admin msix while working in polling mode

BugLink: http://bugs.launchpad.net/bugs/1701575

Fixes: 1738cd3e ("Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Netanel Belgazal <netanel@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit a2cc5198)
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>

drivers/net/ethernet/amazon/ena/ena_com.c

@@ -61,6 +61,8 @@
 
 #define ENA_MMIO_READ_TIMEOUT 0xFFFFFFFF
 
+#define ENA_REGS_ADMIN_INTR_MASK 1
+
 /*****************************************************************************/
 /*****************************************************************************/
 /*****************************************************************************/
@@ -1454,6 +1456,12 @@ void ena_com_admin_destroy(struct ena_com_dev *ena_dev)
 
 void ena_com_set_admin_polling_mode(struct ena_com_dev *ena_dev, bool polling)
 {
+	u32 mask_value = 0;
+
+	if (polling)
+		mask_value = ENA_REGS_ADMIN_INTR_MASK;
+
+	writel(mask_value, ena_dev->reg_bar + ENA_REGS_INTR_MASK_OFF);
 	ena_dev->admin_queue.polling = polling;
 }