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Re: [PATCH v2 0/2] spapr: Fix device unplug vs CAS or migration
From: |
David Gibson |
Subject: |
Re: [PATCH v2 0/2] spapr: Fix device unplug vs CAS or migration |
Date: |
Mon, 17 Feb 2020 11:31:37 +1100 |
On Fri, Feb 14, 2020 at 04:01:16PM +0100, Greg Kurz wrote:
> While working on getting rid of CAS reboot, I realized that we currently
> don't handle device hot unplug properly in the following situations:
>
> 1) if the device is unplugged between boot and CAS, SLOF doesn't handle
> the even, which is a known limitation. The device hence stays around
> forever (specifically, until some other event is emitted and the guest
> eventually completes the unplug or a reboot). Until we can teach SLOF
> to correctly process the full FDT at CAS, we should trigger a CAS reboot,
> like we already do for hotplug.
>
> 2) if the guest is migrated after the even was emitted but before the
> guest could process it, the destination is unaware of the pending
> unplug operation and doesn't remove the device when the guests
> releases it. The 'unplug_requested' field of the DRC is actually state
> that should be migrated.
>
> Changes since v1:
> - new spapr_drc_transient() helper that covers pending plug and unplug
> situations for both CAS and migration
> - as a mechanical consequence, fix unplug for CAS an migration in the
> same patch
Applied to ppc-for-5.0, thanks.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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