Hello,

Oleksandr, thank you for Cc-ing Andrii. Andrii, thank you for the comment!

On Fri, 15 Jul 2022 15:00:10 +0300 Andrii Chepurnyi andrii.chepurnyi82@gmail.com wrote:

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Hello All,

I faced the mentioned issue recently and just to bring more context here is our setup: We use pvblock backend for Android guest. It starts using u-boot with pvblock support(which frontend doesn't support the persistent grants feature), later it loads and starts the Linux kernel(which frontend supports the persistent grants feature). So in total, we have sequent two different frontends reconnection, the first of which doesn't support persistent grants. So the original patch [1] perfectly solves the original issue and provides the ability to use persistent grants after the reconnection when Linux frontend which supports persistent grants comes into play. At the same time [2] will disable the persistent grants feature for the first and second frontend.

Thank you for this great explanation of your situation.

Is it possible to keep [1] as is?

Yes, my concerns about Max's original patch[1] are conflicting behavior description in the document[1] and different behavior on blkfront-side 'feature_persistent' parameter. I will post Max's patch again with patches for blkfront behavior change and Documents updates.

[1] https://lore.kernel.org/xen-devel/20220121102309.27802-1-sj@kernel.org/

Thanks, SJ

[1] https://lore.kernel.org/xen-devel/20220106091013.126076-1-mheyne@amazon.de/ [2] https://lore.kernel.org/xen-devel/20220714224410.51147-1-sj@kernel.org/

Best regards, Andrii

On Fri, Jul 15, 2022 at 1:15 PM Oleksandr olekstysh@gmail.com wrote:

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On 15.07.22 01:44, SeongJae Park wrote:

Hello all.

Adding Andrii Chepurnyi to CC who have played with the use-case which required reconnect recently and faced some issues with feature_persistent handling.

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