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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, 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 5F054C433ED for ; Thu, 22 Apr 2021 11:54:51 +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 AF5C06144A for ; Thu, 22 Apr 2021 11:54:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF5C06144A Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.115332.219957 (Exim 4.92) (envelope-from ) id 1lZXuj-0001qF-4e; Thu, 22 Apr 2021 11:54:33 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 115332.219957; Thu, 22 Apr 2021 11:54:33 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lZXuj-0001q8-01; Thu, 22 Apr 2021 11:54:33 +0000 Received: by outflank-mailman (input) for mailman id 115332; Thu, 22 Apr 2021 11:54:32 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lZXuh-0001q3-Tl for xen-devel@lists.xenproject.org; Thu, 22 Apr 2021 11:54:31 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 3a7aaf6f-2beb-42a2-a497-6b2370ffaa50; Thu, 22 Apr 2021 11:54:31 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 26D02ADD7; Thu, 22 Apr 2021 11:54:30 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 3a7aaf6f-2beb-42a2-a497-6b2370ffaa50 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1619092470; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I6B62RVRqHjCnKC0L1n5xwh/jCJ1mRG5P7GLWwxTp4A=; b=eqMkSFLPkiwbF8ENT6vscXyV5Rj1YAHUYkiKn78osphK/oVGyHJwnv9Jy2RGGT6+Al2DZ5 7zQuqw2mAZGllF2faDcMr8LYwNyb8gyoJ4UIDCZgvD6mlpIn9AJlgo/72JvKHi511SEC0U e5xx87Tv6d8DVNZhRIR2JZGF5YHZrwY= Subject: Re: [PATCH v10 01/13] x86/mm: rewrite virt_to_xen_l*e To: Hongyan Xia Cc: jgrall@amazon.com, Andrew Cooper , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Wei Liu , xen-devel@lists.xenproject.org References: <0ccd3883b0ec2e05d600bb593f8f0afd058adc43.1619014052.git.hongyxia@amazon.com> From: Jan Beulich Message-ID: Date: Thu, 22 Apr 2021 13:54:30 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <0ccd3883b0ec2e05d600bb593f8f0afd058adc43.1619014052.git.hongyxia@amazon.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 21.04.2021 16:15, Hongyan Xia wrote: > From: Wei Liu > > Rewrite those functions to use the new APIs. Modify its callers to unmap > the pointer returned. Since alloc_xen_pagetable_new() is almost never > useful unless accompanied by page clearing and a mapping, introduce a > helper alloc_map_clear_xen_pt() for this sequence. > > Signed-off-by: Wei Liu > Signed-off-by: Hongyan Xia Reviewed-by: Jan Beulich albeit ... > @@ -4941,33 +4961,33 @@ static l3_pgentry_t *virt_to_xen_l3e(unsigned long v) > if ( !(l4e_get_flags(*pl4e) & _PAGE_PRESENT) ) > { > bool locking = system_state > SYS_STATE_boot; > - l3_pgentry_t *l3t = alloc_xen_pagetable(); > + mfn_t l3mfn; > + l3_pgentry_t *l3t = alloc_mapped_pagetable(&l3mfn); > > if ( !l3t ) > return NULL; > - clear_page(l3t); > + UNMAP_DOMAIN_PAGE(l3t); ... this immediate unmapping (and then re-mapping below) will imo want re-doing down the road as well. Even if it's not a severe performance hit, it's simply odd, at least to me. Jan