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 above issue. Also, the patch renames local variable
"flags" to "ctl" for both MSI and MSIx case.
Signed-off-by: Gavin Shan <shangw@xxxxxxxxxxxxxxxxxx>
---
drivers/vfio/pci/vfio_pci.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 7ba0424..5760ea6 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -190,25 +190,23 @@ static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
} else if (irq_type == VFIO_PCI_MSI_IRQ_INDEX) {
u8 pos;
- u16 flags;
+ u16 ctl;
pos = vdev->pdev->msi_cap;
if (pos) {
pci_read_config_word(vdev->pdev,
- pos + PCI_MSI_FLAGS, &flags);
-
- return 1 << (flags & PCI_MSI_FLAGS_QMASK);
+ pos + PCI_MSI_FLAGS, &ctl);
+ return 1 << ((ctl & PCI_MSI_FLAGS_QMASK) >> 1);
}
} else if (irq_type == VFIO_PCI_MSIX_IRQ_INDEX) {
u8 pos;
- u16 flags;
+ u16 ctl;
pos = vdev->pdev->msix_cap;
if (pos) {
pci_read_config_word(vdev->pdev,
- pos + PCI_MSIX_FLAGS, &flags);
-
- return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
+ pos + PCI_MSIX_FLAGS, &ctl);
+ return (ctl & PCI_MSIX_FLAGS_QSIZE) + 1;
}
} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX)
if (pci_is_pcie(vdev->pdev))
--
1.7.10.4
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