From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40c4sn6XWxzF2Tl for ; Thu, 3 May 2018 16:26:21 +1000 (AEST) Date: Thu, 3 May 2018 15:50:47 +1000 From: Paul Mackerras To: wei.guo.simon@gmail.com Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 04/11] KVM: PPC: fix incorrect element_size for stxsiwx in analyse_instr Message-ID: <20180503055047.GE6795@fergus.ozlabs.ibm.com> References: <1524657284-16706-1-git-send-email-wei.guo.simon@gmail.com> <1524657284-16706-5-git-send-email-wei.guo.simon@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1524657284-16706-5-git-send-email-wei.guo.simon@gmail.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Apr 25, 2018 at 07:54:37PM +0800, wei.guo.simon@gmail.com wrote: > From: Simon Guo > > stwsiwx will place contents of word element 1 of VSR into word > storage of EA. So the element size of stwsiwx should be 4. > > This patch correct the size from 8 to 4. > > Signed-off-by: Simon Guo > --- > arch/powerpc/lib/sstep.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c > index 34d68f1..151d484 100644 > --- a/arch/powerpc/lib/sstep.c > +++ b/arch/powerpc/lib/sstep.c > @@ -2178,7 +2178,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs, > case 140: /* stxsiwx */ > op->reg = rd | ((instr & 1) << 5); > op->type = MKOP(STORE_VSX, 0, 4); > - op->element_size = 8; > + op->element_size = 4; I made the element_size be 8 deliberately because this way, with size=4 but element_size=8, the code will naturally choose the correct word (the least-significant word of the left half) of the register to store into memory. With this change you then need the special case in a later patch for stxsiwx, which you shouldn't need if you don't make this change. Paul.