Re: [Qemu-devel] [PATCH v8 11/12] vfio: register aer resume notification handler for aer resume

[Zhou Jie <zhoujie2011@cn.fujitsu.com>]

ping

On 2016/7/3 12:00, Zhou Jie wrote:
> Hi Alex,
>
> On 2016/6/30 9:45, Zhou Jie wrote:
>> Hi Alex,
>>
>> On 2016/6/30 2:22, Alex Williamson wrote:
>>> On Wed, 29 Jun 2016 16:54:05 +0800
>>> Zhou Jie <zhoujie2011@cn.fujitsu.com> wrote:
>>>
>>>> Hi Alex,
>>>>
>>>>> And yet we have struct pci_dev.broken_intx_masking and we test for
>>>>> working DisINTx via pci_intx_mask_supported() rather than simply
>>>>> looking for a PCIe device.  Some devices are broken and some simply
>>>>> don't follow the spec, so you're going to need to deal with that or
>>>>> exclude those devices.
>>>> For those devices I have no way to disable the INTx.
>>>
>>> disable_irq()?  Clearly vfio-pci already manages these types of devices
>>> and can disable INTx.  This is why I keep suggesting that maybe tearing
>>> the interrupt setup down completely is a more complete and reliable
>>> approach than masking in the command register.  Unless we're going to
>>> exclude such devices from supporting this mode (which I don't condone),
>>> we must deal with them.
>> Thank you for tell me that.
>> Yes, I can use disable_irq to disable the pci device irq.
>> But should I enable the irq after reset?
>> I will dig into it.
>
> I will alter the VFIO driver like following.
> During err occurs and resume:
> 1. Make config space read only.
> 2. Disable INTx/MSI Interrupt.
> 3. Do nothing for bar regions.
>
> The following code will be modified.
> 1. vfio_pci_ioctl
>    add a flag in vfio_device_info for workable_state support
>    return workable_state in "struct vfio_pci_device" when user get info
> 2. vfio_pci_ioctl
>    During err occurs and resume:
>    if (cmd == VFIO_DEVICE_SET_IRQS || VFIO_DEVICE_RESET
>    || VFIO_DEVICE_GET_PCI_HOT_RESET_INFO || VFIO_DEVICE_PCI_HOT_RESET)
>    block for workable_state clearing
> 3. vfio_pci_write
>    During err occurs and resume:
>    ignore and return 0
> 4. vfio_pci_aer_err_detected
>    Set workable_state to false in "struct vfio_pci_device"
>    Disable INTx:
>      If Disable INTx is support
>        disable by PCI_COMMAND
>      else
>        disable by disable_irq function
>    Disable MSI:
>        disable by clearing the "Bus Master Enable" bit of PCI_COMMAND
>
> 5. vfio_pci_aer_resume
>    Set workable_state to true in "struct vfio_pci_device"
>    About INTx:
>      According to the value of "vdev->ctx[0].masked"
>      to decide whether to enable INTx
>    About MSI:
>      After reset the "Bus Master Enable" bit is default to 0.
>      So user should process this after reset.
>
> Sincerely
> Zhou Jie
>
>
>
>

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