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,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 5AEABC2BB55 for ; Thu, 9 Apr 2020 09:42:26 +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 2F28521D91 for ; Thu, 9 Apr 2020 09:42:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2F28521D91 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 4.89) (envelope-from ) id 1jMThK-00059x-EP; Thu, 09 Apr 2020 09:42:10 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jMThJ-00059m-6i for xen-devel@lists.xenproject.org; Thu, 09 Apr 2020 09:42:09 +0000 X-Inumbo-ID: 60ff8734-7a46-11ea-b58d-bc764e2007e4 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 60ff8734-7a46-11ea-b58d-bc764e2007e4; Thu, 09 Apr 2020 09:42:08 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 018D7AC24; Thu, 9 Apr 2020 09:42:06 +0000 (UTC) Subject: Re: [PATCH v2 1/5] x86/shim: map and unmap page tables in replace_va_mapping To: Hongyan Xia References: <7638095024ec3379a8d9ddadfe47e36da168e4dd.1586352238.git.hongyxia@amazon.com> From: Jan Beulich Message-ID: Date: Thu, 9 Apr 2020 11:42:02 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <7638095024ec3379a8d9ddadfe47e36da168e4dd.1586352238.git.hongyxia@amazon.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: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: xen-devel@lists.xenproject.org, =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , julien@xen.org, Wei Liu , Andrew Cooper Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 08.04.2020 15:36, Hongyan Xia wrote: > --- a/xen/arch/x86/pv/shim.c > +++ b/xen/arch/x86/pv/shim.c > @@ -168,16 +168,17 @@ const struct platform_bad_page *__init pv_shim_reserved_pages(unsigned int *size > static void __init replace_va_mapping(struct domain *d, l4_pgentry_t *l4start, > unsigned long va, mfn_t mfn) > { > - l4_pgentry_t *pl4e = l4start + l4_table_offset(va); > - l3_pgentry_t *pl3e = l4e_to_l3e(*pl4e) + l3_table_offset(va); > - l2_pgentry_t *pl2e = l3e_to_l2e(*pl3e) + l2_table_offset(va); > - l1_pgentry_t *pl1e = l2e_to_l1e(*pl2e) + l1_table_offset(va); > + l4_pgentry_t l4e = l4start[l4_table_offset(va)]; > + l3_pgentry_t l3e = l3e_from_l4e(l4e, l3_table_offset(va)); > + l2_pgentry_t l2e = l2e_from_l3e(l3e, l2_table_offset(va)); > + l1_pgentry_t *pl1e = map_l1t_from_l2e(l2e) + l1_table_offset(va); > struct page_info *page = mfn_to_page(l1e_get_mfn(*pl1e)); > > put_page_and_type(page); > > *pl1e = l1e_from_mfn(mfn, (!is_pv_32bit_domain(d) ? L1_PROT > : COMPAT_L1_PROT)); > + UNMAP_DOMAIN_PAGE(pl1e); > } As said before, here and below I think it should be unmap_domain_page(). > --- a/xen/include/asm-x86/page.h > +++ b/xen/include/asm-x86/page.h > @@ -196,6 +196,19 @@ static inline l4_pgentry_t l4e_from_paddr(paddr_t pa, unsigned int flags) > #define map_l2t_from_l3e(x) (l2_pgentry_t *)map_domain_page(l3e_get_mfn(x)) > #define map_l3t_from_l4e(x) (l3_pgentry_t *)map_domain_page(l4e_get_mfn(x)) > > +/* Unlike lYe_to_lXe(), lXe_from_lYe() do not rely on the direct map. */ > +#define l2e_from_l3e(l3e, offset) ({ \ > + const l2_pgentry_t *l2t = map_l2t_from_l3e(l3e); \ > + l2_pgentry_t l2e = l2t[offset]; \ > + UNMAP_DOMAIN_PAGE(l2t); \ > + l2e; }) > + > +#define l3e_from_l4e(l4e, offset) ({ \ > + const l3_pgentry_t *l3t = map_l3t_from_l4e(l4e); \ > + l3_pgentry_t l3e = l3t[offset]; \ > + UNMAP_DOMAIN_PAGE(l3t); \ > + l3e; }) I think l1e_from_l2e() should be introduced at the same time, even if for now it's unused. I also think, like we do elsewhere, that macro-local variables would better have _ suffixes, to avoid possible variable aliasing issues. Jan