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authorGavin Shan <gwshan@linux.vnet.ibm.com>2014-05-30 11:35:54 -0600
committerAlex Williamson <alex.williamson@redhat.com>2014-05-30 11:35:54 -0600
commitfd49c81f080a997aad4b0e73541cd42772b6a772 (patch)
tree280bab4ea61a5a99ec2fcf0199ba7adc41eeacd8 /drivers/vfio
parentb13460b92093b29347e99d6c3242e350052b62cd (diff)
downloadlinux-fd49c81f080a997aad4b0e73541cd42772b6a772.tar.bz2
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>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/pci/vfio_pci.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 85063f1c12d7..010e0f8b8e4f 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -197,8 +197,7 @@ 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;