Re: [net-next 1/8] pci: Add flag indicating device has been assigned by KVM [and Xen]

On Fri, Sep 23, 2011 at 09:41:39PM -0700, Jeff Kirsher wrote:

On Fri, 2011-09-23 at 12:05 -0700, Konrad Rzeszutek Wilk wrote:

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Version 2 of this patch with the modified comment was just posted to

netdev.  Ian Campbell had mentioned that the Xen pciback driver should be
modified to use this flag but I don't believe any patches for it have been
created yet.

http://marc.info/?i=20110729165446.GA6731@dumpdata.com

..
Any plans to support bnx4 and igb with this feature? Any ETA?

Dave,

Please also add this patch to your net-next queue.

From 53cada5f5f614a856f6ea5a09dc565d6a455d7c2 Mon Sep 17 00:00:00 2001

From: Konrad Rzeszutek Wilk <redacted>
Date: Mon, 26 Sep 2011 12:22:01 -0400
Subject: [PATCH] xen/pciback: Add flag indicating device has been assigned by Xen

Device drivers that create and destroy SR-IOV virtual functions via
calls to pci_enable_sriov() and pci_disable_sriov can cause catastrophic
failures if they attempt to destroy VFs while they are assigned to
guest virtual machines.  By adding a flag for use by the Xen PCI back
to indicate that a device is assigned a device driver can check that
flag and avoid destroying VFs while they are assigned and avoid system
failures.

Signed-off-by: Konrad Rzeszutek Wilk <redacted>
---
 drivers/xen/xen-pciback/xenbus.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index 978d2c6..18db31f 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c

@@ -249,6 +249,7 @@ static int xen_pcibk_export_device(struct xen_pcibk_device *pdev,
 		goto out;
 
 	dev_dbg(&dev->dev, "registering for %d\n", pdev->xdev->otherend_id);
+	dev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
 	if (xen_register_device_domain_owner(dev,
 					     pdev->xdev->otherend_id) != 0) {
 		dev_err(&dev->dev, "device has been assigned to another " \

@@ -288,6 +289,7 @@ static int xen_pcibk_remove_device(struct xen_pcibk_device *pdev,
 	}
 
 	dev_dbg(&dev->dev, "unregistering for %d\n", pdev->xdev->otherend_id);
+	dev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
 	xen_unregister_device_domain_owner(dev);
 
 	xen_pcibk_release_pci_dev(pdev, dev);

-- 
1.7.4.1