[PATCH 4.4 67/76] PCI: Do any VF BAR updates before enabling the BARs

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sumit Semwal <sumit.semwal@xxxxxxxxxx>


From: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>

[ Upstream commit f40ec3c748c6912f6266c56a7f7992de61b255ed ]

Previously we enabled VFs and enable their memory space before calling
pcibios_sriov_enable().  But pcibios_sriov_enable() may update the VF BARs:
for example, on PPC PowerNV we may change them to manage the association of
VFs to PEs.

Because 64-bit BARs cannot be updated atomically, it's unsafe to update
them while they're enabled.  The half-updated state may conflict with other
devices in the system.

Call pcibios_sriov_enable() before enabling the VFs so any BAR updates
happen while the VF BARs are disabled.

[bhelgaas: changelog]
Tested-by: Carol Soto <clsoto@xxxxxxxxxx>
Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/pci/iov.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -303,13 +303,6 @@ static int sriov_enable(struct pci_dev *
 			return rc;
 	}
 
-	pci_iov_set_numvfs(dev, nr_virtfn);
-	iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
-	pci_cfg_access_lock(dev);
-	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
-	msleep(100);
-	pci_cfg_access_unlock(dev);
-
 	iov->initial_VFs = initial;
 	if (nr_virtfn < initial)
 		initial = nr_virtfn;
@@ -320,6 +313,13 @@ static int sriov_enable(struct pci_dev *
 		goto err_pcibios;
 	}
 
+	pci_iov_set_numvfs(dev, nr_virtfn);
+	iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
+	pci_cfg_access_lock(dev);
+	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
+	msleep(100);
+	pci_cfg_access_unlock(dev);
+
 	for (i = 0; i < initial; i++) {
 		rc = virtfn_add(dev, i, 0);
 		if (rc)