Re: [Xen-devel] [PATCH v2] xen/pt: fix some pass-thru devices don't work across reboot

[Chao Gao <chao.gao@xxxxxxxxx>]

On Mon, Nov 19, 2018 at 05:55:08AM -0700, Jan Beulich wrote:
>>>> On 19.11.18 at 13:45, <chao.gao@xxxxxxxxx> wrote:
>> Another solution came to my mind:
>> 
>> The intention of Xen setting 'host_maskall' is to mask a single vector. How
>> about converting the host_maskall to mask all vectors when Xen tries to init 
>> the first vector in msix_capability_init()? Actually, on hardware, all
>> vector's mask bit is already set when pciback is performing device reset. So
>> it won't break anything. With commit 69d99d1b223, even a guest has cleared
>> some vectors' mask bit before the convertion, it won't be an issue.
>
>But we already mask vectors in msix_capability_init(). I thought we had
>already settled that if we came through this function before assigning
>the device to a (new or same/restarting) guest, all ought to be fine:
>When we come here for the first entry, we also turn off host_maskall.

Yes, it is reasonable.

>That's why we've been suggesting to go through a release/prepare
>cycle.

Will follow your suggestion.

Thanks
Chao

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