From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60739) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VA7w0-0002D0-FJ for qemu-devel@nongnu.org; Thu, 15 Aug 2013 20:30:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VA7vy-0002u6-Kz for qemu-devel@nongnu.org; Thu, 15 Aug 2013 20:30:32 -0400 Message-ID: <1376613014.4255.128.camel@pasglop> From: Benjamin Herrenschmidt Date: Fri, 16 Aug 2013 10:30:14 +1000 In-Reply-To: References: <7AAF2DA2-1FEF-4ECA-B220-366D94EC70C4@suse.de> <1376552735-2953-1-git-send-email-aik@ozlabs.ru> <520C8C11.6080905@ozlabs.ru> <98FAFA62-3B3A-40E9-8973-705C5F569CEE@suse.de> <520CB2EC.8060105@suse.de> <471DDE4C-6C6F-4F07-BCFB-8765AC88FEF4@suse.de> <520CBFFD.5040100@suse.de> <520CDDBF.9070909@ozlabs.ru> <520CEA00.2020404@suse.de> <1376612417.4255.127.camel@pasglop> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC PATCH v3] powerpc: add PVR mask support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Anthony Liguori , Alexey Kardashevskiy , qemu-devel , Alexander Graf , "open list:PowerPC" , Paul Mackerras , Andreas =?ISO-8859-1?Q?F=E4rber?= On Thu, 2013-08-15 at 19:28 -0500, Anthony Liguori wrote: > On Thu, Aug 15, 2013 at 7:20 PM, Benjamin Herrenschmidt > wrote: > > On Thu, 2013-08-15 at 16:47 +0200, Andreas F=C3=A4rber wrote: > >> comparing values for closest match. So that if you have a v2.4 and Q= EMU > >> knows v2.1 and v2.3 we take v2.3 and fill in the v2.4 PVR. > > > > Another thing to keep in mind is that we will want eventually to supp= ort > > POWER7 compatibility more on POWER8 with HV KVM. I am not certain wha= t > > the "right" way to do it via qemu command line is, whether we would > > have a -cpu entry (-cpu POWER7_COMPAT ?) or such... >=20 > But this doesn't change the hardware PVR value right, just the virtual > PVR that's in the device tree? =20 Right. > Maybe you need to change some state of the virtual VCPU but from a QEMU > point of view, it's still a POWER8 VCPU (it's just in power7 compat mod= e). Sure, as long as TCG does the right thing (some instructions must be forbidden etc...). That's more what I had in mind... > > Additionally, the trick here is that qemu must be able to change its = model > > at runtime (a reset is permitted). This is how PAPR defines the recon= figuration > > reboot (for that and other things). >=20 > I don't think the model changes. It's just a flag in the power8 vcpu s= tate. >=20 > No different IMHO between jumping from real mode to protected mode to > long mode on x86. Ok. Cheers, Ben. > Regards, >=20 > Anthony Liguori >=20 > > IE. The guest kernel will call FW early on, while still operating und= er > > OFW (from prom_init) indicating what it supports, and if that doesn't= include > > P8, we need to reconfigure the CPU model to be P7 compat (we are allo= wed to > > reboot and reload the same kernel, which is generally what pHyp does,= but > > we'd like to try avoiding it as much as possible). > > > > Cheers, > > Ben. > > > > > >