drivers/vfio/pci: Fix wrong MSI interrupt count
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>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 85063f1..010e0f8 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -197,8 +197,7 @@
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;