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Re: [Qemu-devel] [PATCH v2] spapr_drc: don't allow 'empty' DRCs to be un
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From: |
Bharata B Rao |
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Subject: |
Re: [Qemu-devel] [PATCH v2] spapr_drc: don't allow 'empty' DRCs to be unisolated |
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Date: |
Wed, 9 Sep 2015 09:33:29 +0530 |
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User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Tue, Sep 08, 2015 at 06:44:55PM -0500, Michael Roth wrote:
> Logical resources start with allocation-state:UNUSABLE /
> isolation-state:ISOLATED. During hotplug, guests will transition
> them to allocate-state:USABLE, and then to isolate-state:UNISOLATED.
> The former transition does not seem to have any failure path for
> cases where a DRC does not have any resources associated with it to
> allocate for guest, but instead relies on the subsequent
> isolation-state:UNISOLATED transition to indicate failure in this
> situation.
>
> Currently DRC code does not implement this logic, but instead
> tries to indicate failure by refusing the allocation-state:USABLE
> transition. Unfortunately, since that's not a documented failure
> path, guests continue undeterred, causing undefined behavior in
> QEMU and guest code.
>
> Fix this by handling things as PAPR defines (13.7 and 13.7.3.1).
>
> Cc: address@hidden
> Cc: David Gibson <address@hidden>
> Cc: Bharata B Rao <address@hidden>
> Signed-off-by: Michael Roth <address@hidden>
Tested-by: Bharata B Rao <address@hidden>