On Wed, Mar 18, 2015 at 8:58 PM, Michael S. Tsirkin
<address@hidden> wrote:
>On Wed, Mar 18, 2015 at 05:34:50PM +0800, Jason Wang wrote:
>> We current limit the max virtio queues to 64. This is not
sufficient
>> to support multiqueue devices (e.g recent Linux support up to 256
>> tap queues). So this series tries to let virtio to support more
queues.
>> No much works need to be done except:
>> - Introducing transport specific queue limitation.
>> - Let each virtio transport to use specific limit.
>> - Speedup the MSI-X masking and unmasking through per vector
queue
>> list, and increase the maximum MSI-X vectors supported by qemu.
>> - With the above enhancements, increase the maximum number of
>> virtqueues supported by PCI from 64 to 513.
>> - Compat the changes for legacy machine types.
>
>What are the compatibility considerations here?
Two considerations:
1) To keep msix bar size to 4K for legacy machine types
2) Limit the pci queue max to 64 for legacy machine types