linux-kernel - [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs

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Message-Id: <1467283993-3185-3-git-send-email-xyjxie@linux.vnet.ibm.com>
Date:	Thu, 30 Jun 2016 18:53:08 +0800
From:	Yongji Xie <xyjxie@...ux.vnet.ibm.com>
To:	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org, linux-doc@...r.kernel.org
Cc:	bhelgaas@...gle.com, alex.williamson@...hat.com, aik@...abs.ru,
	benh@...nel.crashing.org, paulus@...ba.org, mpe@...erman.id.au,
	corbet@....net, warrier@...ux.vnet.ibm.com,
	zhong@...ux.vnet.ibm.com, nikunj@...ux.vnet.ibm.com,
	gwshan@...ux.vnet.ibm.com
Subject: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs

VF BARs are read-only zeroes according to SRIOV spec,
the normal way(writing BARs) of allocating resources wouldn't
be applied to VFs. The VFs' resources would be allocated
when we enable SR-IOV capability. So we should not try to
reassign alignment after we enable VFs. It's meaningless
and will release the allocated resources which leads to a bug.

Signed-off-by: Yongji Xie <xyjxie@...ux.vnet.ibm.com>
---
 drivers/pci/pci.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index be8f72c..6ae02de 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4822,6 +4822,10 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
 	resource_size_t align, size;
 	u16 command;
 
+	/* We should never try to reassign VF's alignment */
+	if (dev->is_virtfn)
+		return;
+
 	/* check if specified PCI is target device to reassign */
 	align = pci_specified_resource_alignment(dev);
 	if (!align)
-- 
1.7.9.5