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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 870EEC47422 for ; Fri, 26 Jan 2024 13:02:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rTLpi-00026k-So; Fri, 26 Jan 2024 08:01:23 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rTLpM-0001yY-Tw for qemu-devel@nongnu.org; Fri, 26 Jan 2024 08:01:10 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rTLpJ-0007SS-P7 for qemu-devel@nongnu.org; Fri, 26 Jan 2024 08:01:00 -0500 Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4TLyR24xWvz6K9L1; Fri, 26 Jan 2024 20:57:50 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id 3D275140AB8; Fri, 26 Jan 2024 21:00:50 +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 15.1.2507.35; Fri, 26 Jan 2024 13:00:49 +0000 Date: Fri, 26 Jan 2024 13:00:48 +0000 To: CC: , , , , , , , , , Fan Ni Subject: Re: [PATCH v3 4/9] hw/mem/cxl_type3: Add support to create DC regions to type3 memory devices Message-ID: <20240126130048.000042f4@Huawei.com> In-Reply-To: <20240124152316.0000281c@Huawei.com> References: <20231107180907.553451-1-nifan.cxl@gmail.com> <20231107180907.553451-5-nifan.cxl@gmail.com> <20240124152316.0000281c@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: lhrpeml500006.china.huawei.com (7.191.161.198) To lhrpeml500005.china.huawei.com (7.191.163.240) Received-SPF: pass client-ip=185.176.79.56; envelope-from=jonathan.cameron@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Jonathan Cameron From: Jonathan Cameron via Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, 24 Jan 2024 15:23:16 +0000 Jonathan Cameron wrote: > On Tue, 7 Nov 2023 10:07:08 -0800 > nifan.cxl@gmail.com wrote: > > > From: Fan Ni > > > > With the change, when setting up memory for type3 memory device, we can > > create DC regions. > > A property 'num-dc-regions' is added to ct3_props to allow users to pass the > > number of DC regions to create. To make it easier, other region parameters > > like region base, length, and block size are hard coded. If needed, > > these parameters can be added easily. > > > > With the change, we can create DC regions with proper kernel side > > support as below: > > > > region=$(cat /sys/bus/cxl/devices/decoder0.0/create_dc_region) > > echo $region> /sys/bus/cxl/devices/decoder0.0/create_dc_region > > echo 256 > /sys/bus/cxl/devices/$region/interleave_granularity > > echo 1 > /sys/bus/cxl/devices/$region/interleave_ways > > > > echo "dc0" >/sys/bus/cxl/devices/decoder2.0/mode > > echo 0x40000000 >/sys/bus/cxl/devices/decoder2.0/dpa_size > > > > echo 0x40000000 > /sys/bus/cxl/devices/$region/size > > echo "decoder2.0" > /sys/bus/cxl/devices/$region/target0 > > echo 1 > /sys/bus/cxl/devices/$region/commit > > echo $region > /sys/bus/cxl/drivers/cxl_region/bind > > > > Signed-off-by: Fan Ni > Hi Fan, a few comments inline. > > Jonathan > > > --- > > hw/mem/cxl_type3.c | 35 +++++++++++++++++++++++++++++++++++ > > 1 file changed, 35 insertions(+) > > > > diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c > > index 754c885cd1..2d67d2015c 100644 > > --- a/hw/mem/cxl_type3.c > > +++ b/hw/mem/cxl_type3.c > > @@ -721,6 +721,36 @@ static void ct3d_reg_write(void *opaque, hwaddr offset, uint64_t value, > > } > > } > > > > +static int cxl_create_dc_regions(CXLType3Dev *ct3d) > > +{ > > + int i; > > + uint64_t region_base = 0; > > + uint64_t region_len = 2 * GiB; > > + uint64_t decode_len = 8; /* 8*256MB */ > > If decode len is going to be div 256MiB then we need > a name for that field that makes it clear that it is. > > decode_len_256mbytes or something like that and maybe > region_len_bytes to keep things consistent. > > Why the spec didn't make our life easier and define decode length > in bytes with some bits that must be zero is beyond me... > > > I think we need to make this at least optionally configurable or based > in some fashion on the provided memory backend (divide that up > by number of regions with appropriate rounding perhaps?) This seems to be a mid patch set confusion.. It's fixed in patch 7. Whilst applying I've made this 2GiB here. Jonathan