linux-kernel - [PATCH 4.9 59/93] PCI: Ignore BAR updates on virtual functions

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Date:   Mon, 20 Mar 2017 18:51:34 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>,
        Gavin Shan <gwshan@...ux.vnet.ibm.com>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.9 59/93] PCI: Ignore BAR updates on virtual functions

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

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

From: Bjorn Helgaas <bhelgaas@...gle.com>

[ Upstream commit 63880b230a4af502c56dde3d4588634c70c66006 ]

VF BARs are read-only zero, so updating VF BARs will not have any effect.
See the SR-IOV spec r1.1, sec 3.4.1.11.

We already ignore these updates because of 70675e0b6a1a ("PCI: Don't try to
restore VF BARs"); this merely restructures it slightly to make it easier
to split updates for standard and SR-IOV BARs.

Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Reviewed-by: Gavin Shan <gwshan@...ux.vnet.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/pci/pci.c       |    4 ----
 drivers/pci/setup-res.c |    5 ++---
 2 files changed, 2 insertions(+), 7 deletions(-)

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -564,10 +564,6 @@ static void pci_restore_bars(struct pci_
 {
 	int i;
 
-	/* Per SR-IOV spec 3.4.1.11, VF BARs are RO zero */
-	if (dev->is_virtfn)
-		return;
-
 	for (i = 0; i < PCI_BRIDGE_RESOURCES; i++)
 		pci_update_resource(dev, i);
 }
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -34,10 +34,9 @@ static void pci_std_update_resource(stru
 	int reg;
 	struct resource *res = dev->resource + resno;
 
-	if (dev->is_virtfn) {
-		dev_warn(&dev->dev, "can't update VF BAR%d\n", resno);
+	/* Per SR-IOV spec 3.4.1.11, VF BARs are RO zero */
+	if (dev->is_virtfn)
 		return;
-	}
 
 	/*
 	 * Ignore resources for unimplemented BARs and unused resource slots