[PATCH] [SCSI] qla2xxx: Handle the INTx not connected while passing through

[Shivaprasad G Bhat <sbhat@linux.ibm.com>]

The PCI_INTERRUPT_PIN reports if the device supports the INTx.
However, when the device is assigned to a guest via vfio, the
PCI_INTERRUPT_PIN is set to 0(i.e none) if the line is not
connected and|or the platform cannot route the interrupt.

In such cases, the guest PCI_INTERRUPT_PIN is 0 and the port
number becomes -1(255, uint8_t underflow) for qla[25|27|28]xx and
qla2031 devices. The flt_region_nvram is never set, and subsequently
the lun detection fails. Below warnings show the NVRAM configuration
failure.

 []-0073:1: Inconsistent NVRAM checksum=0xffffffc0 id=HCAM version=0x100.
 []-0074:1: Falling back to functioning (yet invalid -- WWPN) defaults.
 []-0076:1: NVRAM configuration failed.

The patch handles the case, and sets the port_no to devfn like
its done everywhere else.

Reference: commit 2bd42b03ab6b ("vfio/pci: Virtualize zero INTx PIN if no pdev->irq")
Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
---
 drivers/scsi/qla2xxx/qla_os.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 72b1c28e4dae..a8d6a0a021f4 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -2803,11 +2803,16 @@ qla2x00_set_isp_flags(struct qla_hw_data *ha)
 	else {
 		/* Get adapter physical port no from interrupt pin register. */
 		pci_read_config_byte(ha->pdev, PCI_INTERRUPT_PIN, &ha->port_no);
-		if (IS_QLA25XX(ha) || IS_QLA2031(ha) ||
-		    IS_QLA27XX(ha) || IS_QLA28XX(ha))
-			ha->port_no--;
-		else
-			ha->port_no = !(ha->port_no & 1);
+		if (ha->port_no == 0) {
+			/* None of INT[A|B|C|D], may be virtualized by vfio */
+			ha->port_no = PCI_FUNC(ha->pdev->devfn);
+		} else {
+			if (IS_QLA25XX(ha) || IS_QLA2031(ha) ||
+			    IS_QLA27XX(ha) || IS_QLA28XX(ha))
+				ha->port_no--;
+			else
+				ha->port_no = !(ha->port_no & 1);
+		}
 	}
 
 	ql_dbg_pci(ql_dbg_init, ha->pdev, 0x000b,