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 321FDC3DA7A for ; Fri, 6 Jan 2023 04:18:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231318AbjAFESP (ORCPT ); Thu, 5 Jan 2023 23:18:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229881AbjAFESN (ORCPT ); Thu, 5 Jan 2023 23:18:13 -0500 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15D38192A3; Thu, 5 Jan 2023 20:18:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1672978690; x=1704514690; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=EJ99zGke5SZh6gZ65kHYJO251QjbQMEaDGPaMs8wAzE=; b=CbyG3GC4YLer1neUAZaMNGD4HLhevcUQpVGMfx/4qZ+7m0Ss4TPfVan4 8CdnjIgoeUDebp9BWWG9PZ50eFi4rS/DFKffhsF846AMO1XalTrKQqfjl XYEGTef7mSY8R1vWKvKrlWILixPI2U7Z6+BRfLTleJM7bMDGpZ3fKz8TY XypYjTs2zuL3CLCX2h+bG3lIoF7G5dOPYyWfCXht/+0grr0l5y9b0YlVG G+ZtnkKvHOu3OjvlR7Bo/Yv0ruUWPiJYjaiWg04f2FSlMEEDL7ZyGXjkt HDHTbD28MsdolLD1f7hoGMfgDNY6TeyisTmCC8iIN9VDKasBQM6JIjTp1 Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10581"; a="323651270" X-IronPort-AV: E=Sophos;i="5.96,304,1665471600"; d="scan'208";a="323651270" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jan 2023 20:18:09 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10581"; a="744504828" X-IronPort-AV: E=Sophos;i="5.96,304,1665471600"; d="scan'208";a="744504828" Received: from chaop.bj.intel.com (HELO localhost) ([10.240.193.75]) by FMSMGA003.fm.intel.com with ESMTP; 05 Jan 2023 20:17:58 -0800 Date: Fri, 6 Jan 2023 12:13:46 +0800 From: Chao Peng To: Vishal Annapurve Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org, Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Arnd Bergmann , Naoya Horiguchi , Miaohe Lin , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , tabba@google.com, Michael Roth , mhocko@suse.com, wei.w.wang@intel.com Subject: Re: [PATCH v10 9/9] KVM: Enable and expose KVM_MEM_PRIVATE Message-ID: <20230106041346.GA2288017@chaop.bj.intel.com> Reply-To: Chao Peng References: <20221202061347.1070246-1-chao.p.peng@linux.intel.com> <20221202061347.1070246-10-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Thu, Jan 05, 2023 at 12:38:30PM -0800, Vishal Annapurve wrote: > On Thu, Dec 1, 2022 at 10:20 PM Chao Peng wrote: > > > > +#ifdef CONFIG_HAVE_KVM_RESTRICTED_MEM > > +static bool restrictedmem_range_is_valid(struct kvm_memory_slot *slot, > > + pgoff_t start, pgoff_t end, > > + gfn_t *gfn_start, gfn_t *gfn_end) > > +{ > > + unsigned long base_pgoff = slot->restricted_offset >> PAGE_SHIFT; > > + > > + if (start > base_pgoff) > > + *gfn_start = slot->base_gfn + start - base_pgoff; > > There should be a check for overflow here in case start is a very big > value. Additional check can look like: > if (start >= base_pgoff + slot->npages) > return false; > > > + else > > + *gfn_start = slot->base_gfn; > > + > > + if (end < base_pgoff + slot->npages) > > + *gfn_end = slot->base_gfn + end - base_pgoff; > > If "end" is smaller than base_pgoff, this can cause overflow and > return the range as valid. There should be additional check: > if (end < base_pgoff) > return false; Thanks! Both are good catches. The improved code: static bool restrictedmem_range_is_valid(struct kvm_memory_slot *slot, pgoff_t start, pgoff_t end, gfn_t *gfn_start, gfn_t *gfn_end) { unsigned long base_pgoff = slot->restricted_offset >> PAGE_SHIFT; if (start >= base_pgoff + slot->npages) return false; else if (start <= base_pgoff) *gfn_start = slot->base_gfn; else *gfn_start = start - base_pgoff + slot->base_gfn; if (end <= base_pgoff) return false; else if (end >= base_pgoff + slot->npages) *gfn_end = slot->base_gfn + slot->npages; else *gfn_end = end - base_pgoff + slot->base_gfn; if (*gfn_start >= *gfn_end) return false; return true; } Thanks, Chao > > > > + else > > + *gfn_end = slot->base_gfn + slot->npages; > > + > > + if (*gfn_start >= *gfn_end) > > + return false; > > + > > + return true; > > +} > > +