From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932139Ab1BUDrR (ORCPT ); Sun, 20 Feb 2011 22:47:17 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:51501 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755681Ab1BUDrP (ORCPT ); Sun, 20 Feb 2011 22:47:15 -0500 Message-ID: <4D61E058.9080201@cn.fujitsu.com> Date: Mon, 21 Feb 2011 11:47:36 +0800 From: Lai Jiangshan User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: "kvm@vger.kernel.org" , LKML , Avi Kivity , Marcelo Tosatti Subject: [PATCH] kvm: allow RO page when atomic && !write_fault X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-02-21 11:46:05, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-02-21 11:46:14, Serialize complete at 2011-02-21 11:46:14 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Atomic-able hva_to_pfn() patches and allow-read-only-page patches are merged almost the same time. But hva_to_pfn() does not handle these two issues well together. When @atomic && !@write_fault && host-is-read-only-page-mapped the code will return fault_page, actually, it will be better if we return the pfn of the read-only-page. Signed-off-by: Lai Jiangshan --- diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 1fa0d29..f49cfc0 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1060,31 +1060,27 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic, BUG_ON(!write_fault && !writable); if (writable) - *writable = true; + *writable = write_fault; if (atomic || async) - npages = __get_user_pages_fast(addr, 1, 1, page); + npages = __get_user_pages_fast(addr, 1, write_fault, page); if (unlikely(npages != 1) && !atomic) { might_sleep(); - - if (writable) - *writable = write_fault; - npages = get_user_pages_fast(addr, 1, write_fault, page); + } - /* map read fault as writable if possible */ - if (unlikely(!write_fault) && npages == 1) { - struct page *wpage[1]; + /* map read fault as writable if possible */ + if (unlikely(!write_fault) && npages == 1) { + struct page *wpage[1]; - npages = __get_user_pages_fast(addr, 1, 1, wpage); - if (npages == 1) { - *writable = true; - put_page(page[0]); - page[0] = wpage[0]; - } - npages = 1; + npages = __get_user_pages_fast(addr, 1, 1, wpage); + if (npages == 1) { + *writable = true; + put_page(page[0]); + page[0] = wpage[0]; } + npages = 1; } if (unlikely(npages != 1)) {