[dpdk-dev] [PATCH v5 6/6] virtio: return 1 to tell the upper layer we don't take over this device

[Huawei Xie <huawei.xie@intel.com>]

virtio PMD could use IO port to configure the virtio device without
using UIO/VFIO driver in legacy mode.

There are two issues with previous implementation:
1) virtio PMD will take over the virtio device(s) blindly even if not
intended for DPDK.
2) driver conflict between virtio PMD and virtio-net kernel driver.

This patch checks if there is kernel driver other than UIO/VFIO managing
the virtio device before using port IO.

If legacy_virtio_resource_init fails and kernel driver other than
VFIO/UIO is managing the device ,return 1 to tell the upper layer we
don't take over this device.
For all other IO port mapping errors, return -1.

Note than if VFIO/UIO fails, now we don't fall back to port IO.

Fixes: da978dfdc43b ("virtio: use port IO to get PCI resource")

Signed-off-by: Huawei Xie <huawei.xie@intel.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Acked-by: David Marchand <david.marchand@6wind.com>
---
 drivers/net/virtio/virtio_ethdev.c |  6 ++++--
 drivers/net/virtio/virtio_pci.c    | 16 +++++++++++++++-
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index caa970c..06bddd7 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1015,6 +1015,7 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev)
 	struct virtio_net_config *config;
 	struct virtio_net_config local_config;
 	struct rte_pci_device *pci_dev;
+	int ret;
 
 	RTE_BUILD_BUG_ON(RTE_PKTMBUF_HEADROOM < sizeof(struct virtio_net_hdr));
 
@@ -1037,8 +1038,9 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev)
 
 	pci_dev = eth_dev->pci_dev;
 
-	if (vtpci_init(pci_dev, hw) < 0)
-		return -1;
+	ret = vtpci_init(pci_dev, hw);
+	if (ret)
+		return ret;
 
 	/* Reset the device although not necessary at startup */
 	vtpci_reset(hw);
diff --git a/drivers/net/virtio/virtio_pci.c b/drivers/net/virtio/virtio_pci.c
index 85fbe88..98fc370 100644
--- a/drivers/net/virtio/virtio_pci.c
+++ b/drivers/net/virtio/virtio_pci.c
@@ -622,6 +622,13 @@ next:
 	return 0;
 }
 
+/*
+ * Return -1:
+ *   if there is error mapping with VFIO/UIO.
+ *   if port map error when driver type is KDRV_NONE.
+ * Return 1 if kernel driver is managing the device.
+ * Return 0 on success.
+ */
 int
 vtpci_init(struct rte_pci_device *dev, struct virtio_hw *hw)
 {
@@ -641,8 +648,15 @@ vtpci_init(struct rte_pci_device *dev, struct virtio_hw *hw)
 	}
 
 	PMD_INIT_LOG(INFO, "trying with legacy virtio pci.");
-	if (legacy_virtio_resource_init(dev, hw) < 0)
+	if (legacy_virtio_resource_init(dev, hw) < 0) {
+		if (dev->kdrv == RTE_KDRV_UNKNOWN &&
+		    dev->devargs->type != RTE_DEVTYPE_WHITELISTED_PCI) {
+			PMD_INIT_LOG(INFO,
+				"skip kernel managed virtio device.");
+			return 1;
+		}
 		return -1;
+	}
 
 	hw->vtpci_ops = &legacy_ops;
 	hw->use_msix = legacy_virtio_has_msix(&dev->addr);
-- 
1.8.1.4