RE: [PATCH v2 1/3] hv: hv_util: move vmbus_open() to a later place

[Jason Wang <jasowang@redhat.com>]

On Tue, Feb 3, 2015 at 11:30 AM, KY Srinivasan <kys@microsoft.com> 
wrote:
> 
> 
>>  -----Original Message-----
>>  From: Jason Wang [mailto:jasowang@redhat.com]
>>  Sent: Monday, February 2, 2015 7:09 PM
>>  To: Dexuan Cui
>>  Cc: gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org; 
>> driverdev-
>>  devel@linuxdriverproject.org; olaf@aepfle.de; apw@canonical.com; KY
>>  Srinivasan; vkuznets@redhat.com; Haiyang Zhang
>>  Subject: RE: [PATCH v2 1/3] hv: hv_util: move vmbus_open() to a 
>> later place
>>  
>>  
>>  
>>  On Mon, Feb 2, 2015 at 6:09 PM, Dexuan Cui <decui@microsoft.com> 
>> wrote:
>>  >>  -----Original Message-----
>>  >>  From: Jason Wang [mailto:jasowang@redhat.com]
>>  >>  Sent: Monday, February 2, 2015 17:36 PM
>>  >>  To: Dexuan Cui
>>  >>  Cc: gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org;
>>  >> driverdev-
>>  >>  devel@linuxdriverproject.org; olaf@aepfle.de; 
>> apw@canonical.com; KY
>>  >> Srinivasan; vkuznets@redhat.com; Haiyang Zhang
>>  >>  Subject: Re: [PATCH v2 1/3] hv: hv_util: move vmbus_open() to a
>>  >> later place
>>  >>
>>  >>
>>  >>
>>  >>  On Mon, Feb 2, 2015 at 12:35 PM, Dexuan Cui 
>> <decui@microsoft.com>
>>  >> wrote:
>>  >>  > Before the line vmbus_open() returns, srv->util_cb can be 
>> already
>>  >> > running  > and the variables, like util_fw_version, are needed 
>> by
>>  >> the  > srv->util_cb.
>>  >>
>>  >>  A questions is why we do this for util only? Can callbacks of 
>> other
>>  >> devices be called before vmbus_open() returns?
>>  > The variables are used in vmbus_prep_negotiate_resp(), which is 
>> only
>>  > for the util devices.
>>  >
>>  > I think the other devices should already handle the similar issue
>>  > properly.
>>  > If this is not the case, we need to fix them too.
>>  
>>  Better to check all the others, e.g in balloon_probe(), it call
>>  hv_set_drvdata() after vmbus_open() and dose several datas setups 
>> in the
>>  middle. If balloon_onchannelcallback() could be called before
>>  hv_set_drvdata(), the code looks wrong.
> 
> Jason,
> 
> For all other device types, the guest initiates the communication 
> with the host and potentially
> negotiates appropriate (supported) version with the host. For the 
> services packaged in the util
> driver, the flow is a little different - the host pushes the version 
> information into the guest. So,
> the fix Dexuan made is only needed in the util driver.
> 
> Regards,
> 
> K. Y 

Thanks, so you mean for other device, it won't get any interrupt before 
guest negotiate the version with host?
> 
>>  
>>  Thanks
>>  
>>  
>