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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6D0AFC3DA7A for ; Fri, 6 Jan 2023 04:19:23 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pDeBO-0006aP-FJ; Thu, 05 Jan 2023 23:18:18 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pDeBL-0006Zu-0C for qemu-devel@nongnu.org; Thu, 05 Jan 2023 23:18:15 -0500 Received: from mga09.intel.com ([134.134.136.24]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pDeBJ-0000fI-2Y for qemu-devel@nongnu.org; Thu, 05 Jan 2023 23:18:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1672978693; x=1704514693; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=EJ99zGke5SZh6gZ65kHYJO251QjbQMEaDGPaMs8wAzE=; b=iAjFy9NktYipfzaOKO69TRb98U9+/AC9DjiF9XIPRF1bnEpA7arQY5pk XfTPIXD9CbzNXmBuY3KBNtgPKhoD5iuEmMD5xMpgQuvDXG0k0NBJieRR6 0bfehhiIYXHrIiImo0BVXmZp+vGoso6NIJtqLec2z+uYz4uRHFfLgf4I2 cDhWNfThCvREcTBh1/hXVljkq7roY/4sYlKpnf9juAzpmJUYyU1vVwRYK BaPMTYIjF+Qf6WLTyvNwvrdnV2/9oHOxHOYLGaGJlB5ZirHPLIzARgJ6h Kd3AcE6C3mlnvTe78BJKcQtILtpZ0plpo28gafQdQKAWgXvN/DSE+NDr+ g==; X-IronPort-AV: E=McAfee;i="6500,9779,10581"; a="323651266" X-IronPort-AV: E=Sophos;i="5.96,304,1665471600"; d="scan'208";a="323651266" 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> 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: Received-SPF: none client-ip=134.134.136.24; envelope-from=chao.p.peng@linux.intel.com; helo=mga09.intel.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Chao Peng Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.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; > > +} > > +