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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 AC9AAC35247 for ; Thu, 6 Feb 2020 19:22:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 85B9D20659 for ; Thu, 6 Feb 2020 19:22:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727919AbgBFTWc (ORCPT ); Thu, 6 Feb 2020 14:22:32 -0500 Received: from mga12.intel.com ([192.55.52.136]:22504 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727630AbgBFTWc (ORCPT ); Thu, 6 Feb 2020 14:22:32 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Feb 2020 11:22:31 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,410,1574150400"; d="scan'208";a="232140746" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.202]) by orsmga003.jf.intel.com with ESMTP; 06 Feb 2020 11:22:30 -0800 Date: Thu, 6 Feb 2020 11:22:30 -0800 From: Sean Christopherson To: Peter Xu Cc: Paolo Bonzini , Paul Mackerras , Christian Borntraeger , Janosch Frank , David Hildenbrand , Cornelia Huck , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, Christoffer Dall , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= Subject: Re: [PATCH v5 14/19] KVM: Clean up local variable usage in __kvm_set_memory_region() Message-ID: <20200206192230.GE13067@linux.intel.com> References: <20200121223157.15263-1-sean.j.christopherson@intel.com> <20200121223157.15263-15-sean.j.christopherson@intel.com> <20200206190641.GA700495@xz-x1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200206190641.GA700495@xz-x1> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Thu, Feb 06, 2020 at 02:06:41PM -0500, Peter Xu wrote: > On Tue, Jan 21, 2020 at 02:31:52PM -0800, Sean Christopherson wrote: > > [...] > > > @@ -1101,52 +1099,55 @@ int __kvm_set_memory_region(struct kvm *kvm, > > if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) > > return -EINVAL; > > > > - slot = id_to_memslot(__kvm_memslots(kvm, as_id), id); > > - base_gfn = mem->guest_phys_addr >> PAGE_SHIFT; > > - npages = mem->memory_size >> PAGE_SHIFT; > > - > > - if (npages > KVM_MEM_MAX_NR_PAGES) > > - return -EINVAL; > > - > > /* > > * Make a full copy of the old memslot, the pointer will become stale > > * when the memslots are re-sorted by update_memslots(). > > */ > > - old = *slot; > > + tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id); > > + old = *tmp; > > + tmp = NULL; > > Shall we keep this chunk to the patch where it will be used? Other > than that, it looks good to me. I assume you're talking about doing this instead of using @tmp? old = *id_to_memslot(__kvm_memslots(kvm, as_id), id); It's obviously possible, but I really like resulting diff for __kvm_set_memory_region() in "KVM: Terminate memslot walks via used_slots" when tmp is used. @@ -1104,8 +1203,13 @@ int __kvm_set_memory_region(struct kvm *kvm, * when the memslots are re-sorted by update_memslots(). */ tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id); - old = *tmp; - tmp = NULL; + if (tmp) { + old = *tmp; + tmp = NULL; + } else { + memset(&old, 0, sizeof(old)); + old.id = id; + }