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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 9E7F7C433DF for ; Fri, 31 Jul 2020 14:58:50 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7845F206E6 for ; Fri, 31 Jul 2020 14:58:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7845F206E6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1WUW-00081I-8N; Fri, 31 Jul 2020 14:58:36 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1WUU-00081A-QJ for xen-devel@lists.xenproject.org; Fri, 31 Jul 2020 14:58:34 +0000 X-Inumbo-ID: 4dbf3d12-d33e-11ea-8e51-bc764e2007e4 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 4dbf3d12-d33e-11ea-8e51-bc764e2007e4; Fri, 31 Jul 2020 14:58:33 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 37517AD76; Fri, 31 Jul 2020 14:58:46 +0000 (UTC) Subject: Ping: [PATCH 3/5] x86/PV: drop a few misleading paging_mode_refcounts() checks From: Jan Beulich To: Andrew Cooper , Wei Liu , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= References: <9f8d0c4d-dec2-0175-09df-51d5e11c88e1@suse.com> Message-ID: Date: Fri, 31 Jul 2020 16:58:30 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <9f8d0c4d-dec2-0175-09df-51d5e11c88e1@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: George Dunlap , "xen-devel@lists.xenproject.org" , Tim Deegan Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 15.07.2020 11:59, Jan Beulich wrote: > The filling and cleaning up of v->arch.guest_table in new_guest_cr3() > was apparently inconsistent so far: There was a type ref acquired > unconditionally for the new top level page table, but the dropping of > the old type ref was conditional upon !paging_mode_refcounts(). Mirror > this also to arch_set_info_guest(). > > Also move new_guest_cr3()'s #ifdef to around the function - both callers > now get built only when CONFIG_PV, i.e. no need to retain a stub. > > Signed-off-by: Jan Beulich While I've got an ack from Tim, I think I need either an ack from Andrew or someone's R-b in order to commit this. Thanks, Jan > --- a/xen/arch/x86/domain.c > +++ b/xen/arch/x86/domain.c > @@ -1122,8 +1122,6 @@ int arch_set_info_guest( > > if ( !cr3_page ) > rc = -EINVAL; > - else if ( paging_mode_refcounts(d) ) > - /* nothing */; > else if ( cr3_page == v->arch.old_guest_table ) > { > v->arch.old_guest_table = NULL; > @@ -1144,8 +1142,7 @@ int arch_set_info_guest( > case -ERESTART: > break; > case 0: > - if ( !compat && !VM_ASSIST(d, m2p_strict) && > - !paging_mode_refcounts(d) ) > + if ( !compat && !VM_ASSIST(d, m2p_strict) ) > fill_ro_mpt(cr3_mfn); > break; > default: > @@ -1166,7 +1163,7 @@ int arch_set_info_guest( > > if ( !cr3_page ) > rc = -EINVAL; > - else if ( !paging_mode_refcounts(d) ) > + else > { > rc = get_page_type_preemptible(cr3_page, PGT_root_page_table); > switch ( rc ) > --- a/xen/arch/x86/mm.c > +++ b/xen/arch/x86/mm.c > @@ -3149,9 +3149,9 @@ int vcpu_destroy_pagetables(struct vcpu > return rc; > } > > +#ifdef CONFIG_PV > int new_guest_cr3(mfn_t mfn) > { > -#ifdef CONFIG_PV > struct vcpu *curr = current; > struct domain *d = curr->domain; > int rc; > @@ -3220,7 +3220,7 @@ int new_guest_cr3(mfn_t mfn) > > pv_destroy_ldt(curr); /* Unconditional TLB flush later. */ > > - if ( !VM_ASSIST(d, m2p_strict) && !paging_mode_refcounts(d) ) > + if ( !VM_ASSIST(d, m2p_strict) ) > fill_ro_mpt(mfn); > curr->arch.guest_table = pagetable_from_mfn(mfn); > update_cr3(curr); > @@ -3231,30 +3231,24 @@ int new_guest_cr3(mfn_t mfn) > { > struct page_info *page = mfn_to_page(old_base_mfn); > > - if ( paging_mode_refcounts(d) ) > - put_page(page); > - else > - switch ( rc = put_page_and_type_preemptible(page) ) > - { > - case -EINTR: > - case -ERESTART: > - curr->arch.old_guest_ptpg = NULL; > - curr->arch.old_guest_table = page; > - curr->arch.old_guest_table_partial = (rc == -ERESTART); > - rc = -ERESTART; > - break; > - default: > - BUG_ON(rc); > - break; > - } > + switch ( rc = put_page_and_type_preemptible(page) ) > + { > + case -EINTR: > + case -ERESTART: > + curr->arch.old_guest_ptpg = NULL; > + curr->arch.old_guest_table = page; > + curr->arch.old_guest_table_partial = (rc == -ERESTART); > + rc = -ERESTART; > + break; > + default: > + BUG_ON(rc); > + break; > + } > } > > return rc; > -#else > - ASSERT_UNREACHABLE(); > - return -EINVAL; > -#endif > } > +#endif > > #ifdef CONFIG_PV > static int vcpumask_to_pcpumask( > >