From: Bharata B Rao <bharata@linux.vnet.ibm.com>
To: Michael Roth <mdroth@linux.vnet.ibm.com>
Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [Qemu-devel] [PATCH v2] spapr_drc: don't allow 'empty' DRCs to be unisolated
Date: Wed, 9 Sep 2015 09:33:29 +0530 [thread overview]
Message-ID: <20150909040329.GC17433@in.ibm.com> (raw)
In-Reply-To: <1441755895-8920-1-git-send-email-mdroth@linux.vnet.ibm.com>
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: qemu-ppc@nongnu.org
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Tested-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
next prev parent reply other threads:[~2015-09-09 4:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-08 23:44 [Qemu-devel] [PATCH v2] spapr_drc: don't allow 'empty' DRCs to be unisolated Michael Roth
2015-09-09 4:03 ` Bharata B Rao [this message]
2015-09-09 4:10 ` David Gibson
2015-09-09 17:19 ` Michael Roth
2015-09-10 1:18 ` David Gibson
2015-09-10 2:50 ` Michael Roth
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