[added,to,the,4.1,stable,tree] PCI: Do any VF BAR updates before enabling the BARs

Message ID 20180118205908.3220-79-alexander.levin@microsoft.com
State New
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Series
  • [added,to,the,4.1,stable,tree] PCI: Do any VF BAR updates before enabling the BARs
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Commit Message

Sasha Levin Jan. 18, 2018, 9 p.m.
From: Sumit Semwal <sumit.semwal@linaro.org>


This patch has been added to the  stable tree. If you have any
objections, please let us know.

-- 
2.11.0

Patch

===============

[ 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@us.ibm.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/pci/iov.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 846d4f604ebd..089a1f41e44e 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -302,13 +302,6 @@  static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 			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;
@@ -319,6 +312,13 @@  static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 		return retval;
 	}
 
+	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)