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 D265FC001DE for ; Fri, 21 Jul 2023 22:33:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230406AbjGUWdU (ORCPT ); Fri, 21 Jul 2023 18:33:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39600 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229841AbjGUWdT (ORCPT ); Fri, 21 Jul 2023 18:33:19 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3A293A86 for ; Fri, 21 Jul 2023 15:33:17 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5707177ff8aso24295497b3.2 for ; Fri, 21 Jul 2023 15:33:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689978797; x=1690583597; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=7T9EVRBobAr4a8JPgfiIjIX72kF/VyhERBKOIDOEvTo=; b=N3JmIIRFuucWrTRji2j76NW5FMl4jS4wLA3POQW0VLRrR4sFhmKgj7pRUj3gSs0yqe WZvjiVqpyglaAnq94LWefXiOIlgXr/PrbktD6W+TBAFf6s+alvi+gxgQyH8TNpVAsODx OCRkSmym8Xr89af+taUXT0Vhz6Xh0SqYzK++E+LxDlItaWIfk/xiv3hy/q9bOsyCLBei XOyxBMd+5ThifDUK6/o5f+QTqfW/eyfYM90Y+kU5f1e/gaMgZLzn2OVn9bd0Flf7Aat3 ovp2GWeXuTu2BrzRvrwJog7aZBAUD7Ob8wE6NUPaB8bQmPi6OopUS5w2j6M71SZpRLW7 K0fQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689978797; x=1690583597; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7T9EVRBobAr4a8JPgfiIjIX72kF/VyhERBKOIDOEvTo=; b=jwran0BwNBdnvnez2lEKk9XwNqS//NpYldMd6q+oRxufSER914bPU/VW7h5n7EVJWI 3ey35d3umr1++o00acdMg1Ke/Ddxgj8Mk6ES8huOsXQUsY9cAz4oHE4S2cRF7o6mHMAd Rp3u9MAgLtnNCAqvzMS6nVXpu3ZPNRZNVVo9nDmtRv2sYJ15bhfOtk87m4MKYJUjGVz0 Cen129RyWqgFVNTJrdR/A/R2ZETlsb8VLLvJQRUAXOoBK5LY6w/sXokLEKzj26WJImel tJTjI5SNCSBw+7FXep1spPnBSuO4Uy2PUtBJ8//oVEG8nDmY3u9nYX1x2wUt5Kbqvb1N PZmA== X-Gm-Message-State: ABy/qLYKIsitbya6bwjDemr0AMJSLwJRhAAN214r8Ki3lk1aoEFzFbiB jPljwUu+kKyh3Vc5iJBpVpgp1ZZme/U= X-Google-Smtp-Source: APBJJlHilhePzxpErmYmDQimNKPr2Kn3t6yMJLQXIDH2a2VxS3jSVStiMTfJxkBt/UbXzPR1R9iVHrOiOZs= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:ce82:0:b0:d04:faa6:e62b with SMTP id x124-20020a25ce82000000b00d04faa6e62bmr11683ybe.6.1689978797172; Fri, 21 Jul 2023 15:33:17 -0700 (PDT) Date: Fri, 21 Jul 2023 15:33:15 -0700 In-Reply-To: <20230721222704.GJ25699@ls.amr.corp.intel.com> Mime-Version: 1.0 References: <20230718234512.1690985-1-seanjc@google.com> <20230718234512.1690985-13-seanjc@google.com> <20230721061314.3ls6stdawz53drv3@yy-desk-7060> <20230721222704.GJ25699@ls.amr.corp.intel.com> Message-ID: Subject: Re: [RFC PATCH v11 12/29] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory From: Sean Christopherson To: Isaku Yamahata Cc: Yuan Yao , Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , "Matthew Wilcox (Oracle)" , Andrew Morton , Paul Moore , James Morris , "Serge E. Hallyn" , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Peng , Fuad Tabba , Jarkko Sakkinen , Yu Zhang , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , Vlastimil Babka , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , "Kirill A . Shutemov" Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: On Fri, Jul 21, 2023, Isaku Yamahata wrote: > On Fri, Jul 21, 2023 at 02:13:14PM +0800, > Yuan Yao wrote: > > > +static int kvm_gmem_error_page(struct address_space *mapping, struct page *page) > > > +{ > > > + struct list_head *gmem_list = &mapping->private_list; > > > + struct kvm_memory_slot *slot; > > > + struct kvm_gmem *gmem; > > > + unsigned long index; > > > + pgoff_t start, end; > > > + gfn_t gfn; > > > + > > > + filemap_invalidate_lock_shared(mapping); > > > + > > > + start = page->index; > > > + end = start + thp_nr_pages(page); > > > + > > > + list_for_each_entry(gmem, gmem_list, entry) { > > > + xa_for_each_range(&gmem->bindings, index, slot, start, end - 1) { > > > + for (gfn = start; gfn < end; gfn++) { > > > > Why the start end range used as gfn here ? Math is hard? I almost always mess up these types of things, and then catch my bugs via tests. But I don't have tests for this particular flow... Which reminds me, we need tests for this :-) Hopefully error injection provides most of what we need? > > the page->index is offset of inode's page cache mapping and > > gmem address space, IIUC, gfn calculation should follow same > > way as kvm_gmem_invalidate_begin(). > > Also instead of sending signal multiple times, we can utilize lsb argument. As Vishal pointed out, this code shouldn't be sending signals in the first place.