Re: [Qemu-devel] [RFC v9 14/18] vfio: improve vfio_pci_hot_reset to support more case

[Chen Fan <chen.fan.fnst@cn.fujitsu.com>]

On 06/10/2015 05:24 AM, Alex Williamson wrote:
> On Tue, 2015-06-09 at 11:37 +0800, Chen Fan wrote:
>> the vfio_pci_hot_reset differentiate the single and multi in-used
>> devices for reset. but sometimes we own the group without any devices,
>> that also should support hot reset.
> Nope, did you try it?  It can be done, but the group still needs to be
> connected to a container for isolation.
I'm sorry for that. because I have no such host in hand. but I think if
we can keep connect container for each affected group, we also able
to use this method to do host bus reset.

Thanks,
Chen
>
>> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
>> ---
>>   hw/vfio/pci.c | 11 +++++++++++
>>   1 file changed, 11 insertions(+)
>>
>> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
>> index a4e8658..6507f39 100644
>> --- a/hw/vfio/pci.c
>> +++ b/hw/vfio/pci.c
>> @@ -3398,6 +3398,7 @@ static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool single)
>>           PCIHostDeviceAddress host;
>>           VFIOPCIDevice *tmp;
>>           VFIODevice *vbasedev_iter;
>> +        bool found;
>>   
>>           host.domain = devices[i].segment;
>>           host.bus = devices[i].bus;
>> @@ -3427,6 +3428,7 @@ static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool single)
>>               goto out;
>>           }
>>   
>> +        found = false;
>>           /* Prep dependent devices for reset and clear our marker. */
>>           QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
>>               if (vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI) {
>> @@ -3438,12 +3440,21 @@ static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool single)
>>                       ret = -EINVAL;
>>                       goto out_single;
>>                   }
>> +                found = true;
>>                   vfio_pci_pre_reset(tmp);
>>                   tmp->vbasedev.needs_reset = false;
>>                   multi = true;
>>                   break;
>>               }
>>           }
>> +
>> +        /*
>> +         * If we own the group but does not own the device, we also
>> +         * should call hot reset with multi.
>> +         */
>> +        if (!single && !found) {
>> +            multi = true;
>> +        }
>>       }
>>   
>>       if (!single && !multi) {
>
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