On 01/10/2017 11:11 PM, Michael S. Tsirkin wrote:
> On Tue, Jan 10, 2017 at 07:46:17PM +0800, Cao jin wrote:
>>
>>
>> On 01/10/2017 07:04 AM, Michael S. Tsirkin wrote:
>>> On Sat, Dec 31, 2016 at 05:15:36PM +0800, Cao jin wrote:
>>>> Support serious device error recovery
>>>
>>> serious?
>>>
>>
>> Sorry for my poor vocabulary if it confuses people. I wanted to express
>> the meaning that: vfio-pci actually cannot do a real recovery for device
>> even if it provides the callbacks, it relies on the user to do a
>> effective(or word "serious"?) recovery.
>>
>> Welcome the amendment on the commit log.
>
> It's up to Alex, maybe he's able to figure it all out from
> code, but the rest of us could benefit from a description
> of what the patch does from userspace point of view.
>
> Also, is it a pre-requisite of the userspace patches you posted?
>
Yes, it is.
--
Sincerely,
Cao jin
>>>>
>>>> Signed-off-by: Cao jin <caoj.fnst@xxxxxxxxxxxxxx>
>>>> ---
>>>> drivers/vfio/pci/vfio_pci.c | 70 +++++++++++++++++++++++++++++++++++--
>>>> drivers/vfio/pci/vfio_pci_private.h | 2 ++
>>>> 2 files changed, 70 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
>>>> index 712a849..752af20 100644
>>>> --- a/drivers/vfio/pci/vfio_pci.c
>>>> +++ b/drivers/vfio/pci/vfio_pci.c
>>>> @@ -534,6 +534,15 @@ static long vfio_pci_ioctl(void *device_data,
>>>> {
>>>> struct vfio_pci_device *vdev = device_data;
>>>> unsigned long minsz;
>>>> + int ret;
>>>> +
>>>> + if (vdev->aer_recovering && (cmd == VFIO_DEVICE_SET_IRQS ||
>>>> + cmd == VFIO_DEVICE_RESET || cmd == VFIO_DEVICE_PCI_HOT_RESET)) {
>>>> + ret = wait_for_completion_interruptible(
>>>> + &vdev->aer_completion);
>>>
>>> don't split it like that.
>>>
>>>> + if (ret)
>>>> + return ret;
>>>> + }
>>>>
>>>> if (cmd == VFIO_DEVICE_GET_INFO) {
>>>> struct vfio_device_info info;
>>>> @@ -953,6 +962,15 @@ static ssize_t vfio_pci_rw(void *device_data, char __user *buf,
>>>> {
>>>> unsigned int index = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
>>>> struct vfio_pci_device *vdev = device_data;
>>>> + int ret;
>>>> +
>>>> + /* block all kinds of access during host recovery */
>>>> + if (vdev->aer_recovering) {
>>>> + ret = wait_for_completion_interruptible(
>>>> + &vdev->aer_completion);
>>>> + if (ret)
>>>> + return ret;
>>>> + }
>>>>
>>>> if (index >= VFIO_PCI_NUM_REGIONS + vdev->num_regions)
>>>> return -EINVAL;
>>>> @@ -1117,6 +1135,7 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>>> vdev->irq_type = VFIO_PCI_NUM_IRQS;
>>>> mutex_init(&vdev->igate);
>>>> spin_lock_init(&vdev->irqlock);
>>>> + init_completion(&vdev->aer_completion);
>>>>
>>>> ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
>>>> if (ret) {
>>>> @@ -1176,6 +1195,9 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
>>>> {
>>>> struct vfio_pci_device *vdev;
>>>> struct vfio_device *device;
>>>> + u32 uncor_status;
>>>> + unsigned int aer_cap_offset;
>>>> + int ret;
>>>>
>>>> device = vfio_device_get_from_dev(&pdev->dev);
>>>> if (device == NULL)
>>>> @@ -1187,10 +1209,29 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
>>>> return PCI_ERS_RESULT_DISCONNECT;
>>>> }
>>>>
>>>> + /*
>>>> + * get device's uncorrectable error status as soon as possible,
>>>
>>> should be "Get".
>>>
>>>> + * and signal it to user space. The later we read it, the possibility
>>>> + * the register value is mangled grows.
>>>> + */
>>>> + aer_cap_offset = pci_find_ext_capability(vdev->pdev, PCI_EXT_CAP_ID_ERR);
>>>> + ret = pci_read_config_dword(vdev->pdev, aer_cap_offset +
>>>> + PCI_ERR_UNCOR_STATUS, &uncor_status);
>>>> + if (ret)
>>>> + return PCI_ERS_RESULT_DISCONNECT;
>>>> +
>>>> + pr_info("device %d got AER detect notification. uncorrectable error status = 0x%x\n", pdev->devfn, uncor_status);//to be removed
>>>
>>> Pls drop this.
>>>
>>>> mutex_lock(&vdev->igate);
>>>>
>>>> - if (vdev->err_trigger)
>>>> - eventfd_signal(vdev->err_trigger, 1);
>>>> + vdev->aer_recovering = true;
>>>> + reinit_completion(&vdev->aer_completion);
>>>> +
>>>> + if (vdev->err_trigger && uncor_status) {
>>>> + pr_info("device %d signal uncor status 0x%x to user",
>>>> + pdev->devfn, uncor_status);
>>>> + /* signal uncorrectable error status to user space */
>>>> + eventfd_signal(vdev->err_trigger, uncor_status);
>>>> + }
>>>>
>>>> mutex_unlock(&vdev->igate);
>>>>
>>>> @@ -1199,8 +1240,33 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
>>>> return PCI_ERS_RESULT_CAN_RECOVER;
>>>> }
>>>>
>>>> +static void vfio_pci_aer_resume(struct pci_dev *pdev)
>>>> +{
>>>> + struct vfio_pci_device *vdev;
>>>> + struct vfio_device *device;
>>>> +
>>>> + device = vfio_device_get_from_dev(&pdev->dev);
>>>> + if (device == NULL)
>>>> + return;
>>>> +
>>>> + vdev = vfio_device_data(device);
>>>> + if (vdev == NULL) {
>>>> + vfio_device_put(device);
>>>> + return;
>>>> + }
>>>> +
>>>> + mutex_lock(&vdev->igate);
>>>> + vdev->aer_recovering = false;
>>>> + mutex_unlock(&vdev->igate);
>>>> +
>>>> + complete_all(&vdev->aer_completion);
>>>> +
>>>> + vfio_device_put(device);
>>>> +}
>>>> +
>>>> static const struct pci_error_handlers vfio_err_handlers = {
>>>> .error_detected = vfio_pci_aer_err_detected,
>>>> + .resume = vfio_pci_aer_resume,
>>>> };
>>>>
>>>> static struct pci_driver vfio_pci_driver = {
>>>> diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
>>>> index 8a7d546..ba8471f 100644
>>>> --- a/drivers/vfio/pci/vfio_pci_private.h
>>>> +++ b/drivers/vfio/pci/vfio_pci_private.h
>>>> @@ -83,6 +83,8 @@ struct vfio_pci_device {
>>>> bool bardirty;
>>>> bool has_vga;
>>>> bool needs_reset;
>>>> + bool aer_recovering;
>>>> + struct completion aer_completion;
>>>> struct pci_saved_state *pci_saved_state;
>>>> int refcnt;
>>>> struct eventfd_ctx *err_trigger;
>>>> --
>>>> 1.8.3.1
>>>>
>>>>
>>>
>>> How about some explanation about what is going on here? All these
>>> changes seem racy since any number of errors can trigger at any time.
>>>
>>
>>
>
>
> .
>
--
Sincerely,
Cao jin
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