From patchwork Tue Apr 6 19:22:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 12185769 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=-18.8 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,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 A18C2C433B4 for ; Tue, 6 Apr 2021 19:23:07 +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 5B00661040 for ; Tue, 6 Apr 2021 19:23:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B00661040 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org 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.106269.203261 (Exim 4.92) (envelope-from ) id 1lTrHp-0004Fe-2F; Tue, 06 Apr 2021 19:22:53 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 106269.203261; Tue, 06 Apr 2021 19:22:53 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lTrHo-0004FX-VV; Tue, 06 Apr 2021 19:22:52 +0000 Received: by outflank-mailman (input) for mailman id 106269; Tue, 06 Apr 2021 19:22:50 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lTrHm-0004FS-SV for xen-devel@lists.xenproject.org; Tue, 06 Apr 2021 19:22:50 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lTrHl-0005d3-P7; Tue, 06 Apr 2021 19:22:49 +0000 Received: from 54-240-197-235.amazon.com ([54.240.197.235] helo=ufe34d9ed68d054.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lTrHl-0000zd-9m; Tue, 06 Apr 2021 19:22:49 +0000 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" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Message-Id:Date:Subject:Cc:To:From; bh=PrkuCfGhHLJrZ4S+yOEu6s9dgnK1NNTZT78cqa6PGl8=; b=YvMSibRja/Vs2ECLsL57FpEjVl dJUh3M+WZZx8cSxrzl376E8sX3VXWiKPaFR4X8pYdvK0O0B1n4Irhef2cuBFaeIp+xpqM7i5ONEMj 5NZ0j0/k0U6R1mzLtJ2ObHG3/iMz8DHsup96H8Nq1HwIDjzU2cNvNbKP/OIXq4VoD2oA=; From: Julien Grall To: xen-devel@lists.xenproject.org Cc: julien@xen.org, Julien Grall , Andrew Cooper , George Dunlap , Ian Jackson , Jan Beulich , Stefano Stabellini , Wei Liu Subject: [PATCH] xen/page_alloc: Remove dead code in alloc_domheap_pages() Date: Tue, 6 Apr 2021 20:22:46 +0100 Message-Id: <20210406192246.15657-1-julien@xen.org> X-Mailer: git-send-email 2.17.1 From: Julien Grall Since commit 1aac966e24e9 "xen: support RAM at addresses 0 and 4096", bits_to_zone() will never return 0 and it is expected that we have minimum 2 zones. Therefore the check in alloc_domheap_pages() is unnecessary and can be removed. However, for sanity, it is replaced with an ASSERT(). Also take the opportunity to check atbuild time that NR_ZONES is minimum 2. This bug was discovered and resolved using Coverity Static Analysis Security Testing (SAST) by Synopsys, Inc. Signed-off-by: Julien Grall Reviewed-by: Jan Beulich --- xen/common/page_alloc.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 1744e6faa5c4..68e47d963842 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -457,6 +457,12 @@ static long total_avail_pages; static DEFINE_SPINLOCK(heap_lock); static long outstanding_claims; /* total outstanding claims by all domains */ +static void __init __maybe_unused build_assertions(void) +{ + /* Zone 0 is reserved for Xen, so we at least need two zones to function.*/ + BUILD_BUG_ON(NR_ZONES < 2); +} + unsigned long domain_adjust_tot_pages(struct domain *d, long pages) { long dom_before, dom_after, dom_claimed, sys_before, sys_after; @@ -2340,8 +2346,9 @@ struct page_info *alloc_domheap_pages( bits = domain_clamp_alloc_bitsize(memflags & MEMF_no_owner ? NULL : d, bits ? : (BITS_PER_LONG+PAGE_SHIFT)); - if ( (zone_hi = min_t(unsigned int, bits_to_zone(bits), zone_hi)) == 0 ) - return NULL; + + zone_hi = min_t(unsigned int, bits_to_zone(bits), zone_hi); + ASSERT(zone_hi != 0); if ( memflags & MEMF_no_owner ) memflags |= MEMF_no_refcount;