From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:43631) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SzZgX-0001CS-A7 for qemu-devel@nongnu.org; Thu, 09 Aug 2012 16:50:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SzZgW-0003W0-89 for qemu-devel@nongnu.org; Thu, 09 Aug 2012 16:50:25 -0400 Message-ID: <50242286.4070302@freescale.com> Date: Thu, 9 Aug 2012 15:50:14 -0500 From: Scott Wood MIME-Version: 1.0 References: <1340492856-21126-1-git-send-email-agraf@suse.de> <1340492856-21126-57-git-send-email-agraf@suse.de> <61CF2032-367D-4F3A-A845-BB92B35C334B@suse.de> <5022EAE0.7040103@freescale.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH 56/72] PPC: e500: Use new MPIC dt format List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: qemu-ppc Mailing List , qemu-devel qemu-devel On 08/09/2012 03:48 PM, Alexander Graf wrote: > > On 09.08.2012, at 00:40, Scott Wood wrote: > >> On 08/08/2012 04:16 PM, Alexander Graf wrote: >>> >>> On 24.06.2012, at 01:07, Alexander Graf wrote: >>> >>>> Due to popular demand, we're updating the way we generate the MPIC >>>> node and interrupt lines based on what the current state of art is. >>>> >>>> Requested-by: Scott Wood >>>> Signed-off-by: Alexander Graf >>> >>> Hey Scott, >>> >>> This patch breaks SMP for me. The reason for the breakage is that >>> Linux does some things differently when it finds an fsl,mpic instead >>> of a generic openpic. I have assembled logs between a working version >>> (compatible openpic) and a broken version (compatible fsl,mpic) with >>> guest and host debug turned on. >>> >>> Maybe you have an idea what's going wrong. >> >> IIRC QEMU is missing support for large vectors, which is probably >> breaking IPIs. A recent change to Linux has it assuming it can use >> large vectors when it sees fsl,mpic, as we're running out of vectors (on >> p4080 MSIs collided with the arbitrarily chosen timer vector, and on >> t4240 the normal internal interrupts alone go beyond 256). >> >> We need to get the enhancements from our internal KVM MPIC back into QEMU. > > Ok, so the quick fix for 1.2 would be to revert to the old compatible > name. Can we leave the 4-field interrupt numbers or do we need to > revert the whole patch? In theory you shouldn't have 4-cell interrupt numbers without fsl,mpic, but I don't think it will actually break in Linux -- the extra cells should just be ignored. -Scott