On 01/05/2012 05:24 AM, Ian Campbell wrote:
On Thu, 2012-01-05 at 00:46 +0000, Konrad Rzeszutek Wilk wrote: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.Currently I thought the toolstack was supposed to do the reset (by writing to the reset node in sysfs) as it was (de)assigning devices to/from guests. That's not to say that there isn't an argument for preferring to do it kernels side but it would be interesting to make that argument explicitly. I guess the toolstack doesn't currently save/restore the configuration state, could it though? I guess the state is all available in sysfs. On
pci_reset_function() saves the config state before doing a fcn-level reset. the libvirt toolstack handles the unbind/reset/bind functionality and is used by kvm for it's device assignment.
the other hand the kernel provides us with a very handy function which Just Does It... Ian.Signed-off-by: Konrad Rzeszutek Wilk<konrad.wilk@xxxxxxxxxx> --- 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;-- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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