From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9EAAEC77B7F for ; Fri, 19 May 2023 13:42:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229965AbjESNmm (ORCPT ); Fri, 19 May 2023 09:42:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230116AbjESNml (ORCPT ); Fri, 19 May 2023 09:42:41 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B4A8BB for ; Fri, 19 May 2023 06:42:39 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4QN7Js2DVxz67PjK; Fri, 19 May 2023 21:40:45 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Fri, 19 May 2023 14:42:36 +0100 Date: Fri, 19 May 2023 14:42:34 +0100 From: Jonathan Cameron To: , Michael Tsirkin , Fan Ni CC: , Ira Weiny , "Alison Schofield" , Michael Roth , Philippe =?ISO-8859-1?Q?Mathieu-Daud=E9?= , Dave Jiang , Markus Armbruster , "Daniel P . =?ISO-8859-1?Q?Berrang=E9?=" , Eric Blake , Mike Maslenkin , =?ISO-8859-1?Q?Marc-Andr=E9?= Lureau , Thomas Huth Subject: Re: [PATCH v5 3/6] bswap: Add the ability to store to an unaligned 24 bit field Message-ID: <20230519144223.0000551a@huawei.com> In-Reply-To: <20230519123353.00004a00@huawei.com> References: <20230423162013.4535-1-Jonathan.Cameron@huawei.com> <20230423162013.4535-4-Jonathan.Cameron@huawei.com> <20230519123353.00004a00@huawei.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml100001.china.huawei.com (7.191.160.183) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org On Fri, 19 May 2023 12:33:53 +0100 Jonathan Cameron wrote: > On Sun, 23 Apr 2023 17:20:10 +0100 > Jonathan Cameron wrote: > > > From: Ira Weiny > > > > CXL has 24 bit unaligned fields which need to be stored to. CXL is > > specified as little endian. > > > > Define st24_le_p() and the supporting functions to store such a field > > from a 32 bit host native value. > > > > The use of b, w, l, q as the size specifier is limiting. So "24" was > > used for the size part of the function name. > > > > Reviewed-by: Fan Ni > > Signed-off-by: Ira Weiny > > Signed-off-by: Jonathan Cameron > > This doesn't work for s390 (probably big endian hosts in general) > > I'll post a new version of the series with adjusted logic shortly. > I think all we can do is special case the 24 bit logic in the block > dealing with big vs little endian accessors. > > Something like the following. > I'll drop Fan's tag as this is a substantial change. Fan, if you can > take a look at v6 when I post it that would be great. > > I'm having issues with gitlab CI minutes running out on my fork. > Hopefully I can get that resolved and test this properly. Got this tested using a cross compile in docker via make docker-test-build@debian-x390x-cross and a bunch of docker config. Anyhow, will send out new version of patches 3-6 shortly. Thanks, Jonathan > > diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h > index 91ed9c7e2c..f546b1fc06 100644 > --- a/include/qemu/bswap.h > +++ b/include/qemu/bswap.h > @@ -40,11 +40,13 @@ static inline void bswap64s(uint64_t *s) > #if HOST_BIG_ENDIAN > #define be_bswap(v, size) (v) > #define le_bswap(v, size) glue(__builtin_bswap, size)(v) > +#define le_bswap24(v) bswap24(v) > #define be_bswaps(v, size) > #define le_bswaps(p, size) \ > do { *p = glue(__builtin_bswap, size)(*p); } while (0) > #else > #define le_bswap(v, size) (v) > +#define le_bswap24(v) (v) > #define be_bswap(v, size) glue(__builtin_bswap, size)(v) > #define le_bswaps(v, size) > #define be_bswaps(p, size) \ > @@ -319,7 +321,7 @@ static inline void stw_le_p(void *ptr, uint16_t v) > > static inline void st24_le_p(void *ptr, uint32_t v) > { > - st24_he_p(ptr, le_bswap(v, 24)); > + st24_he_p(ptr, le_bswap24(v)); > } > > static inline void stl_le_p(void *ptr, uint32_t v) > > > > > --- > > v5: > > - Added assertion that upper bits of the input parameter aren't set. > > - Mask value in bswap24s() > > - update docs > > --- > > docs/devel/loads-stores.rst | 1 + > > include/qemu/bswap.h | 25 +++++++++++++++++++++++++ > > 2 files changed, 26 insertions(+) > > > > diff --git a/docs/devel/loads-stores.rst b/docs/devel/loads-stores.rst > > index ad5dfe133e..57b4396f7a 100644 > > --- a/docs/devel/loads-stores.rst > > +++ b/docs/devel/loads-stores.rst > > @@ -36,6 +36,7 @@ store: ``st{size}_{endian}_p(ptr, val)`` > > ``size`` > > - ``b`` : 8 bits > > - ``w`` : 16 bits > > + - ``24`` : 24 bits > > - ``l`` : 32 bits > > - ``q`` : 64 bits > > > > diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h > > index 15a78c0db5..91ed9c7e2c 100644 > > --- a/include/qemu/bswap.h > > +++ b/include/qemu/bswap.h > > @@ -8,11 +8,25 @@ > > #undef bswap64 > > #define bswap64(_x) __builtin_bswap64(_x) > > > > +static inline uint32_t bswap24(uint32_t x) > > +{ > > + assert((x & 0xff000000U) == 0); > > + > > + return (((x & 0x000000ffU) << 16) | > > + ((x & 0x0000ff00U) << 0) | > > + ((x & 0x00ff0000U) >> 16)); > > +} > > + > > static inline void bswap16s(uint16_t *s) > > { > > *s = __builtin_bswap16(*s); > > } > > > > +static inline void bswap24s(uint32_t *s) > > +{ > > + *s = bswap24(*s & 0x00ffffffU); > > +} > > + > > static inline void bswap32s(uint32_t *s) > > { > > *s = __builtin_bswap32(*s); > > @@ -176,6 +190,7 @@ CPU_CONVERT(le, 64, uint64_t) > > * size is: > > * b: 8 bits > > * w: 16 bits > > + * 24: 24 bits > > * l: 32 bits > > * q: 64 bits > > * > > @@ -248,6 +263,11 @@ static inline void stw_he_p(void *ptr, uint16_t v) > > __builtin_memcpy(ptr, &v, sizeof(v)); > > } > > > > +static inline void st24_he_p(void *ptr, uint32_t v) > > +{ > > + __builtin_memcpy(ptr, &v, 3); > > +} > > + > > static inline int ldl_he_p(const void *ptr) > > { > > int32_t r; > > @@ -297,6 +317,11 @@ static inline void stw_le_p(void *ptr, uint16_t v) > > stw_he_p(ptr, le_bswap(v, 16)); > > } > > > > +static inline void st24_le_p(void *ptr, uint32_t v) > > +{ > > + st24_he_p(ptr, le_bswap(v, 24)); > > +} > > + > > static inline void stl_le_p(void *ptr, uint32_t v) > > { > > stl_he_p(ptr, le_bswap(v, 32)); > >