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RE: [Xen-devel] [VTD][PATCH] Do FLR of assigned devices with VT-d

Hi Guy,

If you use "xm destroy" or click "x" on qemu window to destroy guest,
the assigned device may be stayed in a incorrect status. We met that the
irq of the assigned device may be disabled by dom0 after destroy guest,
then all the devices using the same irq can't work any more. We also met
guest complained the device was not in a correct status during its
booting period.

We think there are three places where need invoking FLR function. The
first place is before device assignment, the second one is after
exit/destroy guest, the last one is dynamic reassignment after support
vtd hotplug. In the latter two cases, it is hard to catch the point to
do FLR in qemu.

Randy (Weidong)

Guy Zana wrote:
> That's a good addition, why moving this functionality to the
> hypervisor? BTW, can you give real world example where this was
> needed? 
> Thanks,
> Guy.
>> -----Original Message-----
>> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of
>> Han, Weidong
>> Sent: Thursday, January 24, 2008 4:39 AM
>> To: xen-devel@xxxxxxxxxxxxxxxxxxx
>> Cc: Xu, Anthony; Kay,Allen M
>> Subject: [Xen-devel] [VTD][PATCH] Do FLR of assigned devices with
>> VT-d 
>> Currently there is a pdev_flr() function to do FLR before
>> device assignment in qemu, but most of devices don't have FLR
>> capability. What's more, should do FLR before assignment and
>> deassignment 
>> for keeping correct device status. If the device doesn't have
>> FLR capablility, this patch implemented to enter D3hot and
>> return to D0 to do FLR. And exposed pdev_flr() in VT-d utils,
>> then it can be invoked by assignment and deassignment functions.
>> Signed-off-by: Weidong Han <weidong.han@xxxxxxxxx>
>> Signed-off-by: Anthony Xu <anthony.xu@xxxxxxxxx

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