[ 104/108] xen/pciback: Fix proper FLR steps.

From: Greg Kroah-Hartman
Date: Wed Sep 12 2012 - 19:36:45 EST

From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>

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


From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

commit 80ba77dfbce85f2d1be54847de3c866de1b18a9a upstream.

When we do FLR and save PCI config we did it in the wrong order.
The end result was that if a PCI device was unbind from
its driver, then binded to xen-pciback, and then back to its
driver we would get:

> lspci -s 04:00.0
04:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
13:42:12 # 4 :~/
> echo "0000:04:00.0" > /sys/bus/pci/drivers/pciback/unbind
> modprobe e1000e
e1000e: Intel(R) PRO/1000 Network Driver - 2.0.0-k
e1000e: Copyright(c) 1999 - 2012 Intel Corporation.
e1000e 0000:04:00.0: Disabling ASPM L0s L1
e1000e 0000:04:00.0: enabling device (0000 -> 0002)
xen: registering gsi 48 triggering 0 polarity 1
Already setup the GSI :48
e1000e 0000:04:00.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
e1000e: probe of 0000:04:00.0 failed with error -2

This fixes it by first saving the PCI configuration space, then
doing the FLR.

Reported-by: Ren, Yongjie <yongjie.ren@xxxxxxxxx>
Reported-and-Tested-by: Tobias Geiger <tobias.geiger@xxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/xen/xen-pciback/pci_stub.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -353,16 +353,16 @@ static int __devinit pcistub_init_device
if (err)
goto config_release;

- dev_dbg(&dev->dev, "reseting (FLR, D3, etc) the device\n");
- __pci_reset_function_locked(dev);
/* We need the device active to save the state. */
dev_dbg(&dev->dev, "save state of device\n");
dev_data->pci_saved_state = pci_store_saved_state(dev);
if (!dev_data->pci_saved_state)
dev_err(&dev->dev, "Could not store PCI conf saved state!\n");
+ else {
+ dev_dbg(&dev->dev, "reseting (FLR, D3, etc) the device\n");
+ __pci_reset_function_locked(dev);
+ }
/* Now disable the device (this also ensures some private device
* data is setup before we export)

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