From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37902) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZZWbo-0007Z2-7s for qemu-devel@nongnu.org; Wed, 09 Sep 2015 00:03:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZZWbl-0000rO-1N for qemu-devel@nongnu.org; Wed, 09 Sep 2015 00:03:44 -0400 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:36654) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZZWbk-0000qI-C3 for qemu-devel@nongnu.org; Wed, 09 Sep 2015 00:03:40 -0400 Received: from /spool/local by e28smtp09.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 9 Sep 2015 09:33:37 +0530 Date: Wed, 9 Sep 2015 09:33:29 +0530 From: Bharata B Rao Message-ID: <20150909040329.GC17433@in.ibm.com> References: <1441755895-8920-1-git-send-email-mdroth@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1441755895-8920-1-git-send-email-mdroth@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH v2] spapr_drc: don't allow 'empty' DRCs to be unisolated Reply-To: bharata@linux.vnet.ibm.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Michael Roth Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org, David Gibson 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 > Cc: Bharata B Rao > Signed-off-by: Michael Roth Tested-by: Bharata B Rao