From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x244.google.com (mail-pf0-x244.google.com [IPv6:2607:f8b0:400e:c00::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3xPqr83CBfzDqkr for ; Sun, 6 Aug 2017 03:03:36 +1000 (AEST) Received: by mail-pf0-x244.google.com with SMTP id p13so4853409pfd.4 for ; Sat, 05 Aug 2017 10:03:36 -0700 (PDT) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin , "Gautham R . Shenoy" , Paul Mackerras Subject: [PATCH 12/13] powerpc/64s: idle POWER9 can execute stop in virtual mode Date: Sun, 6 Aug 2017 03:02:40 +1000 Message-Id: <20170805170241.22966-13-npiggin@gmail.com> In-Reply-To: <20170805170241.22966-1-npiggin@gmail.com> References: <20170805170241.22966-1-npiggin@gmail.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The hardware can execute stop in any context, and KVM does not require real mode. This saves a switch to real-mode when going idle. Signed-off-by: Nicholas Piggin --- arch/powerpc/kernel/idle_book3s.S | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index 75746111e2c4..8ac366a51bb5 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -141,7 +141,16 @@ pnv_powersave_common: std r5,_CCR(r1) std r1,PACAR1(r13) +BEGIN_FTR_SECTION + /* + * POWER9 does not require real mode to stop, and does not set + * hwthread_state for KVM (threads don't share MMU context), so + * we can remain in virtual mode for this. + */ + bctr +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) /* + * POWER8 * Go to real mode to do the nap, as required by the architecture. * Also, we need to be in real mode before setting hwthread_state, * because as soon as we do that, another thread can switch -- 2.11.0