Re: [PATCH v2 3/3] virtio: Add a new layer to abstract pci access method

[Tetsuya Mukawa <mukawa@igel.co.jp>]

On 2016/01/29 18:17, Yuanhan Liu wrote:
> On Thu, Jan 28, 2016 at 06:33:32PM +0900, Tetsuya Mukawa wrote:
>> This patch addss function pointers to abstract pci access method.
>> This abstraction layer will be used when virtio-net PMD supports
>> container extension.
>>
>> The below functions abstract how to access to pci configuration space.
>>
>> struct virtio_pci_cfg_ops {
>>         int   (*map)(...);
>>         void  (*unmap)(...);
>>         void *(*get_mapped_addr)(...);
>>         int   (*read)(...);
>> };
>>
>> The pci configuration space has information how to access to virtio
>> device registers. Basically, there are 2 ways to acccess to the
>> registers. One is using portio and the other is using mapped memory.
>> The below functions abstract this access method.
> One question: is there a way to map PCI memory with Qtest? I'm thinking
> if we can keep the io_read/write() for Qtest as well, if so, code could
> be simplified, a lot, IMO.
>

Yes, I agree with you.
But AFAIK, we don't have a way to mmap it from DPDK application.

We may be able to map PCI configuration space to a memory address space
that guest CPU can handle.
But even in this case, I guess we cannot access the memory without qtest
messaging.

Thanks,
Tetsuya