[dpdk-dev] [PATCH] net/virtio: fix use_msix get the wrong value

[Zhiyong Yang <zhiyong.yang@intel.com>]

When running l3fwd-power to test virtio rxq interrupt using vfio
pci noiommu mode, startup fails. In the function virtio_read_caps,
the code if (flags & PCI_MSIX_ENABLE) intends to double check
if vfio msix is enabled or not. However, it is indeed not valid.
Come back to l3fwd-power, use_msix is not assigned to the right
value "1". The patch fixes the issue.

Fixes: cb482cb3a305 ("net/virtio: fix MAC address read")
Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>
---
 drivers/net/virtio/virtio_pci.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/net/virtio/virtio_pci.c b/drivers/net/virtio/virtio_pci.c
index 55b717c03..be5b07a58 100644
--- a/drivers/net/virtio/virtio_pci.c
+++ b/drivers/net/virtio/virtio_pci.c
@@ -580,8 +580,6 @@ get_cfg_addr(struct rte_pci_device *dev, struct virtio_pci_cap *cap)
 	return base + offset;
 }
 
-#define PCI_MSIX_ENABLE 0x8000
-
 static int
 virtio_read_caps(struct rte_pci_device *dev, struct virtio_hw *hw)
 {
@@ -609,14 +607,7 @@ virtio_read_caps(struct rte_pci_device *dev, struct virtio_hw *hw)
 		}
 
 		if (cap.cap_vndr == PCI_CAP_ID_MSIX) {
-			/* Transitional devices would also have this capability,
-			 * that's why we also check if msix is enabled.
-			 * 1st byte is cap ID; 2nd byte is the position of next
-			 * cap; next two bytes are the flags.
-			 */
-			uint16_t flags = ((uint16_t *)&cap)[1];
-
-			if (flags & PCI_MSIX_ENABLE)
+			if (dev->intr_handle.type == RTE_INTR_HANDLE_VFIO_MSIX)
 				hw->use_msix = 1;
 		}
 
-- 
2.13.3