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 8AAB1EE4993 for ; Wed, 23 Aug 2023 15:15:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236906AbjHWPPI (ORCPT ); Wed, 23 Aug 2023 11:15:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233322AbjHWPPG (ORCPT ); Wed, 23 Aug 2023 11:15:06 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A80910C3 for ; Wed, 23 Aug 2023 08:14:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1692803651; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nmWOJ3PgLNwb6XXHu+pQh+YNRDsU+vDPGbdwEescA6k=; b=bYx3ixCNWZGCONUrDDYABMa62gIYOzJBc9DHnISg78YLHUq8uWdVrGlGYCT+p1YOHhCxG9 nvZt3Ry/mPlSWXtcvCNW8kaxHx/2m6h6H35QktX2ZbsN3SAmDmpN0xfP6E35X/79Hl6ccc FFZ2VEXIep3aq+45JpEAVwaXSX9nNE8= Received: from mail-io1-f70.google.com (mail-io1-f70.google.com [209.85.166.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-156-gS-6UN-BO-yfxa_p3z5Yjg-1; Wed, 23 Aug 2023 11:14:10 -0400 X-MC-Unique: gS-6UN-BO-yfxa_p3z5Yjg-1 Received: by mail-io1-f70.google.com with SMTP id ca18e2360f4ac-786d9d4d9a6so539221739f.2 for ; Wed, 23 Aug 2023 08:14:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692803649; x=1693408449; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=nmWOJ3PgLNwb6XXHu+pQh+YNRDsU+vDPGbdwEescA6k=; b=WBDNd/tpVO5L7WpHWMFL9Il+HxzkUTV8CHwiLYJpE5xRWeuNK5uLWR/4HKcFyGB0xi A+wm3adInh9BC+KCQDZDIKJixpPmo+OIDvwc8t5t1wv+lHR/YTfliBQ7c+6H8Wx+OS75 J6Tl9sQ3Ukwgh3diL7IgDg3x8/75cMuuRAsZFQzKt6Kop6mhb/bmCkI+RQ60S+yf+quJ G3DgHvNh1qzkpkDxOydv5Rai/DBzGdlA/9DZfT7ALvwCI3Lpm0pdZP+TIXzKqDxXvAbh kiojhA9Q5gMGq8MKDUC6Ig+NViI3zxEfi+ayDXNGQuSbMt6erQrhVREJ/pjkB71l+du6 NroQ== X-Gm-Message-State: AOJu0YxlifW+sUNPRGS8QRi1hsjBGhKYmPYbzeDXHE8jMnJmOCkXtWCr FwDS3QVEHaB3sqhhwEHnrHMwqzHWNtTFE8GdGiT2jRodrpQE8k3iscA6H5QMvBfoju2eh0clXdS a+vdvbNHa/xqfGAeMrj63G3S9 X-Received: by 2002:a5e:8b04:0:b0:790:a23b:1dfc with SMTP id g4-20020a5e8b04000000b00790a23b1dfcmr3307542iok.9.1692803649368; Wed, 23 Aug 2023 08:14:09 -0700 (PDT) X-Google-Smtp-Source: AGHT+IH1ejXlq1DobE4s847LmD8hNlB4ek7rEulj4rPQgyLGwQUjlN1C1W1HdguCPBUX33+sS3zvSg== X-Received: by 2002:a5e:8b04:0:b0:790:a23b:1dfc with SMTP id g4-20020a5e8b04000000b00790a23b1dfcmr3307519iok.9.1692803649184; Wed, 23 Aug 2023 08:14:09 -0700 (PDT) Received: from redhat.com ([38.15.60.12]) by smtp.gmail.com with ESMTPSA id s24-20020a02ad18000000b00430a69ea278sm3821226jan.167.2023.08.23.08.14.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Aug 2023 08:14:08 -0700 (PDT) Date: Wed, 23 Aug 2023 09:14:07 -0600 From: Alex Williamson To: Ankit Agrawal Cc: Jason Gunthorpe , Yishai Hadas , "shameerali.kolothum.thodi@huawei.com" , "kevin.tian@intel.com" , Aniket Agashe , Neo Jia , Kirti Wankhede , "Tarun Gupta (SW-GPU)" , Vikram Sethi , Andy Currid , Alistair Popple , John Hubbard , Dan Williams , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v7 1/1] vfio/nvgpu: Add vfio pci variant module for grace hopper Message-ID: <20230823091407.0964bd3b.alex.williamson@redhat.com> In-Reply-To: References: <20230822202303.19661-1-ankita@nvidia.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.35; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 23 Aug 2023 14:50:31 +0000 Ankit Agrawal wrote: > >> + if (index == VFIO_PCI_BAR2_REGION_INDEX) { > >> + if (!nvdev->opregion) { > >> + nvdev->opregion = memremap(nvdev->hpa, nvdev->mem_length, MEMREMAP_WB); > >> + if (!nvdev->opregion) > >> + return -ENOMEM; > >> + } > > > > [AW] Seems like this would be susceptible to concurrent accesses causing > > duplicate mappings. > > > > [JG] Needs some kind of locking on opregion > > Right, will add a new lock item in nvdev to control the access to opregion/memmap. > Please let me know if it is preferable to do memremap in open_device instead of > read/write. That's a valid option also, certainly avoids the locking and serialization per access. Thanks, Alex