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 3DE56EB64DD for ; Fri, 11 Aug 2023 16:50:05 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qUVK9-0004rC-9T; Fri, 11 Aug 2023 12:49:17 -0400 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 1qUVK7-0004qO-Kd for qemu-devel@nongnu.org; Fri, 11 Aug 2023 12:49:15 -0400 Received: from mout.gmx.net ([212.227.15.19]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qUVK5-0000nn-Pd for qemu-devel@nongnu.org; Fri, 11 Aug 2023 12:49:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.us; s=s31663417; t=1691772539; x=1692377339; i=fan.ni@gmx.us; bh=A6M2hI18RBeWnhFAQRhVZSf9RInDyT+PXldHCI+QUUI=; h=X-UI-Sender-Class:Date:From:To:Cc:Subject:References:In-Reply-To; b=W5Zd1Pi+/NrFLPrPIKxknGbIsNAalVJptPcYMTfW4ov28xf4UcnvhdFVPnlGpK62lypxJUp 6i46MsbJkmG6K7v+kZJXpDajXl7tlCm86F8+pBvpOJDipXl3q9vvkygGdG/VPD9dzmcm/aXCi X0NZrOrjz1WDGbwHsf9XFIf7sPGEiHtUqt5W0SJKLgCKtyrH7qpLiqfqdKtAjWT7bSkZgSnj9 GEb2S4cuj4qRVI6vjE1bljV8/8KHZBIDwhlfD3cVRAvpoEP4+ArS24Pta7sY/usj+k+QM2Xu3 xWtM8dwEp+EovJxvzAJODuFeesa6W8nfmKGMoNuwDLT3WC9B2LJQ== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from debian ([172.56.208.115]) by mail.gmx.net (mrgmx005 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MgNcz-1prtEz3xiZ-00htYT; Fri, 11 Aug 2023 18:48:59 +0200 Date: Fri, 11 Aug 2023 09:48:46 -0700 From: Fan Ni To: Maverickk 78 Cc: Jonathan Cameron via , Jonathan Cameron , linux-cxl@vger.kernel.org Subject: Re: CXL volatile memory is not listed Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Provags-ID: V03:K1:Yy8qN3fEG+BVpiWgTnMrDPWSegn9up43HgU3mlQRVw5a46ISt6Z sSVmZFflpBzNHCoHzbdWOWOhTg9RnMvzsYciNph//0XFBdw6ui+U7v+4QBV4hrsW1MtHgk1 FTuwVvRcc0rc99U171aLHbqdXINrCZzR7V7oyk9GUBEx2IqQqMeEln/3/E6JWewahGw7JUI M+LdUktDND9dL+tnPrdgA== UI-OutboundReport: notjunk:1;M01:P0:8ErlSrVnU+w=;dXbu97I9r4m0nQqGcyzcM7rrhFJ IwB6POt3I3iuY+TndoQ1I4wOYKbJEZ3jiU1OIquZvElLuKTzXFvue7nXO2GEdgptYCBBK7VNc eSgK/YhxQU2fUPUaHsxE/5XgceCX7K34PPivbZ1rd1d2IxFhwsDOfnwGTUoFFWGnwTKCXlN/p rykTMYMuYwd7DKgna44DjVXlHFtIFyosXirkVsPxuhE1tVO5exjR0v+WaHjqBBfkRPpY/gF6P CU4LCXno+RB9fubiPPeL78zYdeKvkSBl/7MEsVGp279bvBn6gyI1bSEmg9J3jXwRh6Sus6cnm Ki9xKggv5F1myj283YqAUvWus9J+ObHA6smyNzzr5ebCj5sqVfsVkbOQGelqlP0E+H0Tk3slG vWMW33cLmUBeSPbHatKpWQwg+bnKJ9Ym8r8c+ib/51TuE91ZdJa0n/Sr60TICwCzx3cZ6OGpx nL0ITzEiu+kzF7EHHTqd4BwI6ggzQ3OdQS7Ig4vFatkRiXyMsj9wti6rNyBXZ2JfEIOEMankb scDU56VabcYmy5i+eHz70ziBl5nHUlsmn9GmW22jMbYux3gN8uNVrYfQlxOQsuVzXp2byDA+F BC25bPs8+67g3tj6mho6QCR3pihl/fOuH14gF7SaZeOUvtPcd83naMdgnRJhD+MfyNEzqkbGv qbqCgfZijr9aI4+Zw5ovXgYhRm7b8SJPMX+xLNQyD1+ozev+atI2Uy1AykDolOD/+3KvOLbLz dI+aFpg1/2s5K89AibXwCvheaZdCUTooEb5Yr/pj6/TABKHZqPyLIF2wqVB6vWzhoHZ5iAHoz YffjcP83hH0lsrTEg6+x/O6+fyJqtsfW9e6t0bPPGWlytrqB9yGwuqNFYI4DIq21N6jEkqa01 7oS8+QSQptc6Hmsu/BRh4qcIMwvZVrgumw2xXAJUU6c3ef/W6kgWdA8N+5hZLWUqZ1s5nXKS9 yLf70Tm70bGGWpOrp6yJ7fC9cyg= Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=212.227.15.19; envelope-from=fan.ni@gmx.us; helo=mout.gmx.net X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Aug 11, 2023 at 07:52:25AM +0530, Maverickk 78 wrote: > Thanks Fan, > > cxl create-region works like a charm :) > > Since this gets listed as "System Ram(kmem)", I guess the kernel > treats it as regular memory and > allocates it to the applications when needed? > or is there an extra effort needed to make it available for > applications on the host? > Yes. Once it is onlined, you can use it as regular memory. CXL memory will serve as a zero-CPU memory-only NUMA node. You can check it with numactl -H. To use the cxl memory with an app, you can use numactl --membind=3Dnuma_id app_name #numa_id is the dedicated numa node where cxl memory sits. One thing to notes, kvm will not work correctly with Qemu emulation when you try to use cxl memory for an application, so do not enable kvm. Fan > On Thu, 10 Aug 2023 at 22:03, Fan Ni wrote: > > > > On Wed, Aug 09, 2023 at 04:21:47AM +0530, Maverickk 78 wrote: > > > Hello, > > > > > > I am running qemu-system-x86_64 > > > > > > qemu-system-x86_64 --version > > > QEMU emulator version 8.0.92 (v8.1.0-rc2-80-g0450cf0897) > > > > > > qemu-system-x86_64 \ > > > -m 2G,slots=3D4,maxmem=3D4G \ > > > -smp 4 \ > > > -machine type=3Dq35,accel=3Dkvm,cxl=3Don \ > > > -enable-kvm \ > > > -nographic \ > > > -device pxb-cxl,id=3Dcxl.0,bus=3Dpcie.0,bus_nr=3D52 \ > > > -device cxl-rp,id=3Drp0,bus=3Dcxl.0,chassis=3D0,port=3D0,slot=3D0 \ > > > -object memory-backend-file,id=3Dmem0,mem-path=3D/tmp/mem0,size=3D1G= ,share=3Dtrue \ > > > -device cxl-type3,bus=3Drp0,volatile-memdev=3Dmem0,id=3Dcxl-mem0 \ > > > -M cxl-fmw.0.targets.0=3Dcxl.0,cxl-fmw.0.size=3D1G > > > > > > > > > I was expecting the CXL memory to be listed in "System Ram", the lsm= em > > > shows only 2G memory which is System RAM, it's not listing the CXL > > > memory. > > > > > > Do I need to pass any particular parameter in the kernel command lin= e? > > > > > > Is there any documentation available? I followed the inputs provided= in > > > > > > https://lore.kernel.org/linux-mm/Y+CSOeHVLKudN0A6@kroah.com/T/ > > > > > > Is there any documentation/blog listed? > > > > If I remember it correctly, for volatile cxl memory, we need to create= a > > region and then it will be discovered as system memory and shows up. > > > > Try to create a region with "cxl create-region". > > > > Fan > > >