Re: [dpdk-dev] [PATCH v1 0/5] Enable hotplug in vfio

[Jeff Guo <jia.guo@intel.com>]

hi, gaetan


On 8/20/2018 5:15 PM, Gaëtan Rivet wrote:
> Hi Jeff,
>
> On Fri, Aug 17, 2018 at 06:51:26PM +0800, Jeff Guo wrote:
>> As we may know that the process of hotplug is different between igb_uio
>> and vfio. For igb_uio, it could use uevent notification and memory
>> failure handle mechanism for hotplug. But for vfio, when device is be
>> hotplug-out, the uevent can not be detected immediately, because of the
>> vfio kernel module will use a special mechanism to guaranty the pci
>> device would not be deleted until the user space release the resources,
>> so it will use another event “req notifier” at first to notify user space
>> to release resources for hotplug.
>>
>> This patch will add a new interrupt type of req notifier in eal interrupt,
>> and add the new interrupt handler in pci device to handle the req device
>> event. When the req notifier be detected, it can trigger the device event
>> callback process to process for hotplug. With this mechanism, hotplug
>> could be enable in vfio.
>>
> The REQ event seems VFIO specific.
> Why not leave it within the PCI bus, around the vfio glue, and leave the
> EAL unmodified?

Sorry i don' t see if there are any problem. Firstly, as we can see the 
eal interrupt type, it cover the ext/uio/vfio/dev event types, which are 
not general for all platform/bus/driver type.
so i think base on the current framework, the interrupt type structure 
should be considerate as combined set, it could extend for other adding 
interrupts case by case. And secondly, i don't know what
is your way about leave it within the PCI bus, because i need to use the 
eal interrupt epoll to process this req interrupt which is familiar with 
other interrupts. What do you think about that, if you still
have better suggestion, please detail it for clarify.

>> Jeff Guo (5):
>>    eal: add a new req notifier to eal interrupt
>>    eal: add a new req event to device event
>>    eal: modify device event callback process func
>>    pci: add req handler field to generic pci device
>>    vfio: enable vfio hotplug by req notifier handler
>>
>>   drivers/bus/pci/linux/pci_vfio.c                   | 104 +++++++++++++++++++++
>>   drivers/bus/pci/pci_common.c                       |  10 ++
>>   drivers/bus/pci/rte_bus_pci.h                      |   1 +
>>   lib/librte_eal/common/eal_common_dev.c             |   5 +-
>>   lib/librte_eal/common/eal_private.h                |  12 ---
>>   lib/librte_eal/common/include/rte_dev.h            |  20 +++-
>>   lib/librte_eal/common/include/rte_eal_interrupts.h |   1 +
>>   lib/librte_eal/linuxapp/eal/eal_dev.c              |   2 +-
>>   lib/librte_eal/linuxapp/eal/eal_interrupts.c       |  71 ++++++++++++++
>>   lib/librte_ethdev/rte_ethdev.c                     |   3 +-
>>   10 files changed, 212 insertions(+), 17 deletions(-)
>>
>> -- 
>> 2.7.4
>>