Re: [Qemu-devel] [PATCH] virtio-scsi spec: add per-LUN parameter query

[Paolo Bonzini <pbonzini@redhat.com>]

Il 20/08/2012 16:44, McPacino ha scritto:
> 
> 在 2012-8-20 下午9:18，"Paolo Bonzini" <pbonzini@redhat.com
> <mailto:pbonzini@redhat.com>>写道：
>>
>> Il 20/08/2012 11:03, Cong Meng ha scritto:
>> > Each virtio scsi HBA has global request queue limits. But the
> passthrough
>> > LUNs (scsi-generic) come from different host HBAs may have different
> request
>> > queue limits. If the guest sends commands that exceed the host
> limits, the
>> > commands will be rejected by host HAB.
>> >
>> > To address this issue, this patch adds a per-LUN parameter query via
> the control
>> > queue, and defines some parameter query types. The driver can query
> and set the
>> > needed per-LUN parameters if the device enables this feature.
>> >
>> > Signed-off-by: Cong Meng <mc@linux.vnet.ibm.com
> <mailto:mc@linux.vnet.ibm.com>>
>> > --
>> >  virtio-spec.lyx |  218
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> >  1 files changed, 218 insertions(+), 0 deletions(-)
>>
>> Do you have kernel and QEMU patches for this?  That would help me
>> evaluate whether the interface is the correct one.
>>
> yes,I have a demo. I will post it after I polish it tomorrow.
> 
>> In any case, I'd rather have a single command returning all three values
>> (VIRTIO_SCSI_T_LUN_QUEUE_PARAMS), since it's unlikely that you need just
>> one.
> 
> I intend to seperat them one by one. As there is opportunity that other
> new parameters are needed for other features.

You can use more feature bits to dictate which bits are present.

Paolo