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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 5072AC4338F for ; Tue, 10 Aug 2021 09:12:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 37D5961058 for ; Tue, 10 Aug 2021 09:12:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237234AbhHJJNA (ORCPT ); Tue, 10 Aug 2021 05:13:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230039AbhHJJM7 (ORCPT ); Tue, 10 Aug 2021 05:12:59 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8452FC0613D3; Tue, 10 Aug 2021 02:12:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=H3zzJaXcELoe7fwHmHVQFbyT9HpObLcWomqOooPjNsk=; b=NtrCnvhh9LR4naycFbzgkj3XFS jV56VjiVsPy2S3YV/1LdXXzZRKKXfQZfTPMBzilWd2hL43c/3wfSKWdj8sP3C195sneeIM6tG8ODl ibuNY8VntRlgm5qa5oCSHftrOtstNRzOpM47ACyBLWyXwHuo6AXye856kzngkRo82YtelqfPnDKGy xJlvLeKMJruRSsFhqPmQzRQL2jP5QDgViRwfEga6/fdRW1V7Sy3jLLGMVXiLk5p4ZzzbbYBLvAdGP pXVomXDLVzXbt1GUe3YKjDOdNebtqOTHAd4m6LmbQuS9eHVZTDu/1dmFTFFDuqhW2gZO9py/sIt1Q gx+LxoQg==; Received: from [2001:4bb8:184:6215:a004:cea2:5ea9:6eca] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDNna-00BvyP-8T; Tue, 10 Aug 2021 09:11:58 +0000 Date: Tue, 10 Aug 2021 11:11:49 +0200 From: Christoph Hellwig To: Alex Williamson 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: References: <162818167535.1511194.6614962507750594786.stgit@omen> <162818330190.1511194.10498114924408843888.stgit@omen> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <162818330190.1511194.10498114924408843888.stgit@omen> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? > +extern void vfio_pci_test_and_up_write_memory_lock(struct vfio_pci_device > + *vdev); No need for the extern.