Messages in this thread | | | Date | Thu, 05 Jan 2012 13:58:50 -0500 | From | Don Dutile <> | Subject | Re: [Xen-devel] [PATCH 2/5] xen/pciback: Support pci_reset_function, aka FLR or D3 support. |
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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@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; > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
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