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


On Tue, Feb 3, 2015 at 11:40 AM, KY Srinivasan <kys@microsoft.com>
wrote:
>
>
>> -----Original Message-----
>> From: Jason Wang [mailto:jasowang@redhat.com]
>> Sent: Monday, February 2, 2015 7:38 PM
>> To: KY Srinivasan
>> Cc: Dexuan Cui; gregkh@linuxfoundation.org;
>> linux-kernel@vger.kernel.org;
>> driverdev-devel@linuxdriverproject.org; olaf@aepfle.de;
>> apw@canonical.com; vkuznets@redhat.com; Haiyang Zhang
>> Subject: RE: [PATCH v2 1/3] hv: hv_util: move vmbus_open() to a
>> later place
>>
>>
>>
>> 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?
>
> Yes, the guest initiates the version negotiation. Are you seeing
> something different?
>
> K. Y

No, thanks.



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