Re: [Qemu-devel] [PATCH 6/9] vhost-scsi: new device supporting the tcm_vhost Linux kernel module

[Wenchao Xia]

于 2013-5-29 23:10, Badari Pulavarty 写道:
> On 05/29/2013 02:05 AM, Wenchao Xia wrote:
>> 于 2013-5-28 17:00, Wenchao Xia 写道:
>>> 于 2013-5-28 16:33, Asias He 写道:
>>>> On Tue, May 28, 2013 at 10:01:14AM +0200, Paolo Bonzini wrote:
>>>>> Il 28/05/2013 09:13, Wenchao Xia ha scritto:
>>>>>>>> From: Nicholas Bellinger <address@hidden>
>>>>>>>>
>>>>>>>> The WWPN specified in configfs is passed to "-device 
>>>>>>>> vhost-scsi-pci".
>>>>>>>> The tgpt field of the SET_ENDPOINT ioctl is obsolete now, so it is
>>>>>>>> not
>>>>>>>> available from the QEMU command-line.  Instead, I hardcode it to
>>>>>>>> zero.
>>>>>>>>
>>>>>> Hi, Paolo
>>>>>>    Any document about how to config it correctly in configfs, before
>>>>>> invoking qemu with the WWPN number?
>>>>>
>>>>> Unfortunately no, but vhost-scsi doesn't have many knobs (unlike
>>>>> iSCSI for example) so it's quite simple.  Here is an example:
>>>>>
>>>>> cd /sys/kernel/config/target
>>>>> mkdir -p core/fileio_0/fileio
>>>>> echo 'fd_dev_name=/home/pbonzini/test.img,fd_dev_size=5905580032' >
>>>>> core/fileio_0/fileio/control
>>>>> echo 1 > core/fileio_0/fileio/enable
>>>>> mkdir -p vhost/naa.600140554cf3a18e/tpgt_0/lun/lun_0
>>>>> cd vhost/naa.600140554cf3a18e/tpgt_0
>>>>> ln -sf ../../../../../core/fileio_0/fileio/ 
>>>>> lun/lun_0/virtual_scsi_port
>>>>> echo naa.60014053226f0388 > nexus
>>>>>
>>>>> The "nexus" value is the initiator WWN. naa.600140554cf3a18e is the
>>>>> target WWN that you have to pass to "-device vhost-scsi-pci".
>>>>>
>>>>> Paolo
>>>>
>>>> For me, I always use targetcli utils instead of the sysfs interface.
>>>> targetcli in F18 has vhost support now.
>>>>
>>>    Thanks very much for above information, I'll try it for test.
>>>
>>   I have done a basic test of vhost-scsi, following is the result I'd
>> like to post, generally it seems fine:
>>
>> Result:
>>   fdisk/mkfs: fdisk can find it, mke2fs works fine.
>>   mount: can mount it.
>>   file I/O: dd 90M zero to a file in that disk succeed.
> 
> 
> 
> I tried without nested kvm.
> 
>>
>> Issues:
>>   1) in fdisk -l, sometime timeout with dmesg "end_request: I/O error,
>> dev  fd0, sector 0", I guess it is caused by nested KVM that failed
>> to kick host kernel?
> 
> 
> I don't see this issue. Are you sure "fd0" is actually the scsi device ?
> what is "fd0" ?
> 
  I am not sure, it just come out from dmesg when fdisk -l hung, and
following line is "sdb" which is the vhost-scsi device, and fdisk
printing stopped before "sdb" for a few seconds, so I think it's it.
it happened once after my partition operation.
  My instinct opinion is it happens only in nested KVM when host
missed a kick, since following I/O can succeed. Sadly I have no
bare-metal at hand to test as a comparation.

>>   2) in fdisk -l, it shows 512 bytes larger than the parameter I
>> specified in fd_dev_size parameter in configfs on host.(shows
>> 104858112 bytes, see the invocation script below)
>>
> 
> I see the same. For some reason "fdisk -l" in the VM shows
> 512-bytes more than the actual size for the file (on the host).
> 
> Thanks,
> Badari
> 


-- 
Best Regards

Wenchao Xia