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 X-Spam-Level: X-Spam-Status: No, score=-8.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13098C4338F for ; Tue, 10 Aug 2021 15:04:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF8CB60FC4 for ; Tue, 10 Aug 2021 15:04:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242540AbhHJPE3 (ORCPT ); Tue, 10 Aug 2021 11:04:29 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:56371 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241428AbhHJPE2 (ORCPT ); Tue, 10 Aug 2021 11:04:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628607845; 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=saDSmbq1KyQ846SiUJnNdk6f6G6MN7+bgqLynbPPajY=; b=VeVhUEpb7wGosqcqiQNUtoO9xG9XNA2KSSiidTa/VxcJTzpzURGHYPNx1ay90quOXa2efC 7purs2HchEjS/fUahfzPa8UPgWqhFLmQ3vHisXLhVqd67Ma50j0pXTeGpW4r8j7PDOAFUP +W70+vIwC8/HrC7KxNvD1LW9018/TAg= Received: from mail-oo1-f72.google.com (mail-oo1-f72.google.com [209.85.161.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-9-_Kr9kQWyMLmsKlyliHTBaA-1; Tue, 10 Aug 2021 11:04:04 -0400 X-MC-Unique: _Kr9kQWyMLmsKlyliHTBaA-1 Received: by mail-oo1-f72.google.com with SMTP id y10-20020a4ab40a0000b0290285068c6fc0so7170121oon.1 for ; Tue, 10 Aug 2021 08:04:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:organization:mime-version:content-transfer-encoding; bh=saDSmbq1KyQ846SiUJnNdk6f6G6MN7+bgqLynbPPajY=; b=jpHC8BUi5yks8ajewouL3vPjvSG5jhUrnFMzTv1EbqOVXNeg9PjcYHYGHeYOaXVgVu W2kPsPQ9qQBeUIXG0eWA3BsonGcYrtroDxxx+7O8R1boxtQFdGvka+oR6mf2z6qpuNPK 4+CjWTDENlvkDX3XrIL/Mhg8nUyFrqTbaqWbxrnq7c/eyLPo1q0Ih2qlg8MuO6eaTWAF IcTwvHFV+sYeIEiZSLXZnD9/w+ZUtRoYbUii6mAx1v74YtRv2pRxyOFpPfunXBvenVHs DzBXmJoG2X7J4ptH+jtQXQ4H7PDykgzFxmYyz528SNCrOtrOesxnOTyw3/VaW20Pwp19 0HHw== X-Gm-Message-State: AOAM5311SVSicwdv+LDtsimQATkTEybCBeOvAKR5OomE1nOoOjFiB5b7 QVwLajpRUqyoVcF4Jy/80X72qOGYD3HNZE5ikiV+v+JuqAHKHB8rj0B0YExDQvAlwrc1cUnrae8 pHY9+8cCYqQAR X-Received: by 2002:a9d:4e03:: with SMTP id p3mr20862109otf.214.1628607843793; Tue, 10 Aug 2021 08:04:03 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwa8NsTflJyoCSB3QzQu/ldQGo0dEw8Tvkv48rIc4s6fH1Ji0z48X8Eqi491aAosuf+mgaKlg== X-Received: by 2002:a9d:4e03:: with SMTP id p3mr20862079otf.214.1628607843599; Tue, 10 Aug 2021 08:04:03 -0700 (PDT) Received: from redhat.com ([198.99.80.109]) by smtp.gmail.com with ESMTPSA id w13sm2037036otl.41.2021.08.10.08.04.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Aug 2021 08:04:03 -0700 (PDT) Date: Tue, 10 Aug 2021 09:04:02 -0600 From: Alex Williamson To: Christoph Hellwig Cc: Jason Gunthorpe , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, peterx@redhat.com Subject: Re: [PATCH 7/7] vfio/pci: Remove map-on-fault behavior Message-ID: <20210810090402.0a120276.alex.williamson@redhat.com> In-Reply-To: References: <162818167535.1511194.6614962507750594786.stgit@omen> <162818330190.1511194.10498114924408843888.stgit@omen> Organization: Red Hat X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; 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: kvm@vger.kernel.org On Tue, 10 Aug 2021 11:11:49 +0200 Christoph Hellwig wrote: > On Thu, Aug 05, 2021 at 11:08:21AM -0600, Alex Williamson wrote: > > +void vfio_pci_test_and_up_write_memory_lock(struct vfio_pci_device *vdev) > > +{ > > + if (vdev->zapped_bars && __vfio_pci_memory_enabled(vdev)) { > > + WARN_ON(vfio_device_io_remap_mapping_range(&vdev->vdev, > > + VFIO_PCI_INDEX_TO_OFFSET(VFIO_PCI_BAR0_REGION_INDEX), > > + VFIO_PCI_INDEX_TO_OFFSET(VFIO_PCI_ROM_REGION_INDEX) - > > + VFIO_PCI_INDEX_TO_OFFSET(VFIO_PCI_BAR0_REGION_INDEX))); > > + vdev->zapped_bars = false; > > Doing actual work inside a WARN_ON is pretty nasty. Also the non-ONCE > version here will lead to massive log splatter if it actually hits. > > I'd prefer something like: > > loff_t start = VFIO_PCI_INDEX_TO_OFFSET(VFIO_PCI_BAR0_REGION_INDEX); > loff_t end = VFIO_PCI_INDEX_TO_OFFSET(VFIO_PCI_ROM_REGION_INDEX); > > if (vdev->zapped_bars && __vfio_pci_memory_enabled(vdev)) { > if (!vfio_device_io_remap_mapping_range(&vdev->vdev, start, > end - start)) > vdev->zapped_bars = false; > WARN_ON_ONCE(vdev->zapped_bars); > > > vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); > > - vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot); > > What is the story with this appearing earlier and disappearing here > again? We switched from io_remap_pfn_range() which includes this flag implicitly, to vmf_insert_pfn() which does not, and back to io_remap_pfn_range() when the fault handler is removed. > > +extern void vfio_pci_test_and_up_write_memory_lock(struct vfio_pci_device > > + *vdev); > > No need for the extern. Thanks much for the reviews! Alex