From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1LeDou-000129-Sb
	for qemu-devel@nongnu.org; Mon, 02 Mar 2009 14:28:56 -0500
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1LeDot-00011W-Bo
	for qemu-devel@nongnu.org; Mon, 02 Mar 2009 14:28:56 -0500
Received: from [199.232.76.173] (port=46150 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1LeDot-00011C-5d
	for qemu-devel@nongnu.org; Mon, 02 Mar 2009 14:28:55 -0500
Received: from mail-fx0-f175.google.com ([209.85.220.175]:62363)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <blauwirbel@gmail.com>) id 1LeDos-0004C0-NV
	for qemu-devel@nongnu.org; Mon, 02 Mar 2009 14:28:55 -0500
Received: by fxm23 with SMTP id 23so1973425fxm.34
	for <qemu-devel@nongnu.org>; Mon, 02 Mar 2009 11:28:52 -0800 (PST)
MIME-Version: 1.0
In-Reply-To: <E5D5B27F-D0E1-4B14-94F9-854445DC55BB@suse.de>
References: <1236013674-28082-1-git-send-email-agraf@suse.de>
	<1236013674-28082-2-git-send-email-agraf@suse.de>
	<1236013674-28082-3-git-send-email-agraf@suse.de>
	<f43fc5580903021058y16396ee8o3ade84e75790d488@mail.gmail.com>
	<E5D5B27F-D0E1-4B14-94F9-854445DC55BB@suse.de>
Date: Mon, 2 Mar 2009 21:28:52 +0200
Message-ID: <f43fc5580903021128n517f9e25i7b456219e9b84c8c@mail.gmail.com>
From: Blue Swirl <blauwirbel@gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Subject: [Qemu-devel] Re: [PATCH 2/3] PPC64: Implement slbmte
Reply-To: qemu-devel@nongnu.org
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Alexander Graf <agraf@suse.de>
Cc: qemu-devel@nongnu.org

On 3/2/09, Alexander Graf <agraf@suse.de> wrote:
>
>  On 02.03.2009, at 19:58, Blue Swirl wrote:
>
>
> > On 3/2/09, Alexander Graf <agraf@suse.de> wrote:
> >
> > > In order to modify SLB entries on recent PPC64 machines, the slbmte
> > > instruction is used.
> > >
> > > This patch implements the slbmte instruction and makes the "bridge"
> > > mode code use the slb set functions, so we can move the SLB into
> > > the CPU struct later.
> > >
> > > This is required for Linux to run on PPC64.
> > >
> > > Signed-off-by: Alexander Graf <alex@csgraf.de>
> > >
> >
> >
> > >  void ppc_store_sr (CPUPPCState *env, int srnum, target_ulong value)
> > >  {
> > >    LOG_MMU("%s: reg=%d " ADDRX " " ADDRX "\n",
> > >                __func__, srnum, value, env->sr[srnum]);
> > > -    if (env->sr[srnum] != value) {
> > > +    if (env->mmu_model & POWERPC_MMU_64) {
> > >
> >
> >
> > >  target_ulong helper_load_sr (target_ulong sr_num)
> > >  {
> > > +    if (env->mmu_model & POWERPC_MMU_64)
> > > +        return ppc_load_sr(env, sr_num);
> > >    return env->sr[sr_num];
> > >  }
> > >
> >
> > It would be faster to move the MMU model checks to translation time.
> >
>
>  The problem is that we don't know which -cpu the user will give us when we
> run qemu-system-ppc64.
>  Of course we could just make qemu-system-ppc64 not take any non-64 bit
> CPUs, if nobody totally disagrees.

env could contain a pointer to (static const) structure describing the
CPU features. This pointer would be copied to corresponding
DisasContext feature pointer, to be used by the translation functions.

See for example target-sparc: translate.c (CHECK_IU_FEATURE macro) and
helper.c for CPU definitions. IIRC MIPS or ARM have even nicer macros.