diff mbox

[3/4] drivers/vfio/pci: Fix wrong MSI interrupt count

Message ID 1399944924-1200-4-git-send-email-gwshan@linux.vnet.ibm.com
State Superseded
Headers show

Commit Message

Gavin Shan May 13, 2014, 1:35 a.m. UTC 
According PCI local bus specification, the register of Message
Control for MSI (offset: 2, length: 2) has bit#0 to enable or
disable MSI logic and it shouldn't be part contributing to the
calculation of MSI interrupt count. The patch fixes the issue.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 drivers/vfio/pci/vfio_pci.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
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Patch

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 7ba0424..6b8cd07 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -196,8 +196,7 @@  static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
 		if (pos) {
 			pci_read_config_word(vdev->pdev,
 					     pos + PCI_MSI_FLAGS, &flags);
-
-			return 1 << (flags & PCI_MSI_FLAGS_QMASK);
+			return 1 << ((flags & PCI_MSI_FLAGS_QMASK) >> 1);
 		}
 	} else if (irq_type == VFIO_PCI_MSIX_IRQ_INDEX) {
 		u8 pos;