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Subject[PATCH 2/5] xen/pciback: Support pci_reset_function, aka FLR or D3 support.
Date
We use the __pci_reset_function_locked to perform the action.
Also on attaching ("bind") and detaching ("unbind") we save and
restore the configuration states. When the device is disconnected
from a guest we use the "pci_reset_function" to also reset the
device before being passed to another guest.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
drivers/xen/xen-pciback/pci_stub.c | 41 +++++++++++++++++++++++++++++++++--
drivers/xen/xen-pciback/pciback.h | 1 +
2 files changed, 39 insertions(+), 3 deletions(-)
diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
index 8f06e1e..0ce0dc6 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -85,19 +85,34 @@ static struct pcistub_device *pcistub_device_alloc(struct pci_dev *dev)
static void pcistub_device_release(struct kref *kref)
{
struct pcistub_device *psdev;
+ struct xen_pcibk_dev_data *dev_data;

psdev = container_of(kref, struct pcistub_device, kref);
+ dev_data = pci_get_drvdata(psdev->dev);

dev_dbg(&psdev->dev->dev, "pcistub_device_release\n");

xen_unregister_device_domain_owner(psdev->dev);

- /* Clean-up the device */
+ /* Call the reset function which does not take lock as this
+ * is called from "unbind" which takes a device_lock mutex.
+ */
+ __pci_reset_function_locked(psdev->dev);
+ if (pci_load_and_free_saved_state(psdev->dev,
+ &dev_data->pci_saved_state)) {
+ dev_dbg(&psdev->dev->dev, "Could not reload PCI state\n");
+ } else
+ pci_restore_state(psdev->dev);
+
+ /* Disable the device */
xen_pcibk_reset_device(psdev->dev);
+
+ kfree(dev_data);
+ pci_set_drvdata(psdev->dev, NULL);
+
+ /* Clean-up the device */
xen_pcibk_config_free_dyn_fields(psdev->dev);
xen_pcibk_config_free_dev(psdev->dev);
- kfree(pci_get_drvdata(psdev->dev));
- pci_set_drvdata(psdev->dev, NULL);

pci_dev_put(psdev->dev);

@@ -230,7 +245,17 @@ void pcistub_put_pci_dev(struct pci_dev *dev)
/* Cleanup our device
* (so it's ready for the next domain)
*/
+
+ /* This is OK - we are running from workqueue context
+ * and want to inhibit the user from fiddling with 'reset'
+ */
+ pci_reset_function(dev);
+ pci_restore_state(psdev->dev);
+
+ /* This disables the device. */
xen_pcibk_reset_device(found_psdev->dev);
+
+ /* And cleanup up our emulated fields. */
xen_pcibk_config_free_dyn_fields(found_psdev->dev);
xen_pcibk_config_reset_dev(found_psdev->dev);

@@ -325,6 +350,16 @@ static int __devinit pcistub_init_device(struct pci_dev *dev)
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");
+ pci_save_state(dev);
+ 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");
+
/* Now disable the device (this also ensures some private device
* data is setup before we export)
*/
diff --git a/drivers/xen/xen-pciback/pciback.h b/drivers/xen/xen-pciback/pciback.h
index e9b4011..a7def01 100644
--- a/drivers/xen/xen-pciback/pciback.h
+++ b/drivers/xen/xen-pciback/pciback.h
@@ -41,6 +41,7 @@ struct xen_pcibk_device {

struct xen_pcibk_dev_data {
struct list_head config_fields;
+ struct pci_saved_state *pci_saved_state;
unsigned int permissive:1;
unsigned int warned_on_write:1;
unsigned int enable_intx:1;
--
1.7.7.4


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