From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladimir Murzin Subject: Re: [PATCH v3 6/8] ARM: Change MPIDR_AFFINITY_LEVEL to ignore Aff3 Date: Mon, 12 Sep 2016 10:51:08 +0100 Message-ID: <57D67A8C.5080103@arm.com> References: <1473350810-10857-1-git-send-email-vladimir.murzin@arm.com> <1473350810-10857-7-git-send-email-vladimir.murzin@arm.com> <57D2EA7F.9030705@arm.com> <57D677EE.4080706@arm.com> <57D67A06.8090107@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 5D82540F9B for ; Mon, 12 Sep 2016 05:42:32 -0400 (EDT) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mE1m5HS0J0QF for ; Mon, 12 Sep 2016 05:42:31 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2336840C9A for ; Mon, 12 Sep 2016 05:42:30 -0400 (EDT) In-Reply-To: <57D67A06.8090107@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Marc Zyngier , kvmarm@lists.cs.columbia.edu Cc: andre.przywara@arm.com, linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu On 12/09/16 10:48, Marc Zyngier wrote: > On 12/09/16 10:39, Vladimir Murzin wrote: >> On 09/09/16 17:59, Marc Zyngier wrote: >>> On 08/09/16 17:06, Vladimir Murzin wrote: >>>> vgic-v3 driver queries CPU affinity level up to Aff3, which is valid >>>> for arm64. However, for arm up to Aff2 levels are supported, so >>>> querying for third level ends with upper bits of MPIDR are treated as >>>> valid affinity level which is not true. Make sure we report zero for >>>> any affinity level above two. >>>> >>>> Signed-off-by: Vladimir Murzin >>>> --- >>>> arch/arm/include/asm/cputype.h | 3 ++- >>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h >>>> index 1ee94c7..f08fac4 100644 >>>> --- a/arch/arm/include/asm/cputype.h >>>> +++ b/arch/arm/include/asm/cputype.h >>>> @@ -55,9 +55,10 @@ >>>> >>>> #define MPIDR_LEVEL_BITS 8 >>>> #define MPIDR_LEVEL_MASK ((1 << MPIDR_LEVEL_BITS) - 1) >>>> +#define MPIDR_LEVEL_SHIFT(level) (MPIDR_LEVEL_BITS * level) >>>> >>>> #define MPIDR_AFFINITY_LEVEL(mpidr, level) \ >>>> - ((mpidr >> (MPIDR_LEVEL_BITS * level)) & MPIDR_LEVEL_MASK) >>>> + (((mpidr & MPIDR_HWID_BITMASK) >> MPIDR_LEVEL_SHIFT(level)) & MPIDR_LEVEL_MASK) >>>> >>>> #define ARM_CPU_IMP_ARM 0x41 >>>> #define ARM_CPU_IMP_INTEL 0x69 >>>> >>> >>> There is something I don't quite get. Is this patch really necessary? >>> Are there cases where we construct a MPIDR that can have Aff3 set on 32bit? >> >> I've just checked and it seems that I've been keeping the change for >> MPIDR_AFFINITY_LEVEL() since vgic-old era where it was used with >> >> static u32 compress_mpidr(unsigned long mpidr) >> { >> u32 ret; >> >> ret = MPIDR_AFFINITY_LEVEL(mpidr, 0); >> ret |= MPIDR_AFFINITY_LEVEL(mpidr, 1) << 8; >> ret |= MPIDR_AFFINITY_LEVEL(mpidr, 2) << 16; >> ret |= MPIDR_AFFINITY_LEVEL(mpidr, 3) << 24; >> >> return ret; >> } >> >> and now that code gone and nobody passes level 3 into this macro, so I >> can drop this change. >> >> However, I do need MPIDR_LEVEL_SHIFT() macro since it is used in vgic-v3. >> >> Should I leave patch as is or you have something in mind? > > I think that for the sake of keeping the change minimal, it'd be better > to just add the MPIDR_LEVEL_SHIFT macro, and drop the other changes. Noted! Thanks Vladimir > > Thanks, > > M. >