pci_iov: Refuse to create VFs which require ARI if ARI is not available

If a parent downstream port doesn't support ARI, the code would try to
create VFs anyway but then all PCI config space access to those VFs
would fail.

Tested by:	np
Sponsored by:	Chelsio Communications

1 files changed, 12 insertions, 3 deletions

diff --git a/sys/dev/pci/pci_iov.c b/sys/dev/pci/pci_iov.c
index db7210cb729a..ff3ac0e64271 100644
--- a/sys/dev/pci/pci_iov.c
+++ b/sys/dev/pci/pci_iov.c
@@ -435,7 +435,7 @@ out:
  * affects all PFs on the device.
  */
 static int
-pci_iov_set_ari(device_t bus)
+pci_iov_set_ari(device_t bus, bool *ari_enabled)
 {
 	device_t lowest;
 	device_t *devlist;
@@ -443,8 +443,10 @@ pci_iov_set_ari(device_t bus)
 	uint16_t iov_ctl;
 
 	/* If ARI is disabled on the downstream port there is nothing to do. */
-	if (!PCIB_ARI_ENABLED(device_get_parent(bus)))
+	if (!PCIB_ARI_ENABLED(device_get_parent(bus))) {
+		*ari_enabled = false;
 		return (0);
+	}
 
 	error = device_get_children(bus, &devlist, &devcount);
 
@@ -480,6 +482,7 @@ pci_iov_set_ari(device_t bus)
 		device_printf(lowest, "failed to enable ARI\n");
 		return (ENXIO);
 	}
+	*ari_enabled = true;
 	return (0);
 }
 
@@ -683,6 +686,7 @@ pci_iov_config(struct cdev *cdev, struct pci_iov_arg *arg)
 	uint16_t iov_ctl;
 	uint16_t num_vfs, total_vfs;
 	int iov_inited;
+	bool ari_enabled;
 
 	mtx_lock(&Giant);
 	dinfo = cdev->si_drv1;
@@ -713,7 +717,7 @@ pci_iov_config(struct cdev *cdev, struct pci_iov_arg *arg)
 	if (error != 0)
 		goto out;
 
-	error = pci_iov_set_ari(bus);
+	error = pci_iov_set_ari(bus, &ari_enabled);
 	if (error != 0)
 		goto out;
 
@@ -736,6 +740,11 @@ pci_iov_config(struct cdev *cdev, struct pci_iov_arg *arg)
 		goto out;
 	}
 
+	if (!ari_enabled && PCI_RID2SLOT(last_rid) != 0) {
+		error = ENOSPC;
+		goto out;
+	}
+
 	iov_ctl = IOV_READ(dinfo, PCIR_SRIOV_CTL, 2);
 	iov_ctl &= ~(PCIM_SRIOV_VF_EN | PCIM_SRIOV_VF_MSE);
 	IOV_WRITE(dinfo, PCIR_SRIOV_CTL, iov_ctl, 2);