From patchwork Wed May 26 16:11:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 12282239 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 C5D14C47082 for ; Wed, 26 May 2021 16:11:53 +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 75B68611BE for ; Wed, 26 May 2021 16:11:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 75B68611BE 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.132624.247309 (Exim 4.92) (envelope-from ) id 1llw8A-00056E-9f; Wed, 26 May 2021 16:11:38 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 132624.247309; Wed, 26 May 2021 16:11:38 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1llw8A-000567-6g; Wed, 26 May 2021 16:11:38 +0000 Received: by outflank-mailman (input) for mailman id 132624; Wed, 26 May 2021 16:11:36 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1llw88-000561-Ra for xen-devel@lists.xenproject.org; Wed, 26 May 2021 16:11:36 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1llw87-0004fU-6J; Wed, 26 May 2021 16:11:35 +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 1llw86-0003AK-T2; Wed, 26 May 2021 16:11:35 +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=yrQbQMaqTvUXp0yu7HpETMtIwdzmnlOinZ/SB1SX3yg=; b=ioFK1A6SBdCuJWICOD5twMwhhV X4lO53Nvhdb3lw4MXFVRySyx484FDltxvE1TakZPLAgE35lz9h6EQpuqN1BCFKYOjeC3fMZ9PPCrp 2oaKnK3OsxXgVe1TCdcB+ZHgayP295zbTBX2zVFFOKsQkjbtmQMFaDs71VGysWg1UQEw=; 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 v2] xen/page_alloc: Remove dead code in alloc_domheap_pages() Date: Wed, 26 May 2021 17:11:29 +0100 Message-Id: <20210526161129.28572-1-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 switch from min_t() to min() as bits_to_zone() cannot return a negative value. The macro is tweaked to make it clearer. 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 --- Changes in v2: - Remove BUILD_BUG_ON() - Switch from min_t() to min() --- xen/common/page_alloc.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index ace6333c18ea..958ba0cd9256 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -441,7 +441,7 @@ mfn_t __init alloc_boot_pages(unsigned long nr_pfns, unsigned long pfn_align) #define MEMZONE_XEN 0 #define NR_ZONES (PADDR_BITS - PAGE_SHIFT + 1) -#define bits_to_zone(b) (((b) < (PAGE_SHIFT + 1)) ? 1 : ((b) - PAGE_SHIFT)) +#define bits_to_zone(b) (((b) < (PAGE_SHIFT + 1)) ? 1U : ((b) - PAGE_SHIFT)) #define page_to_zone(pg) (is_xen_heap_page(pg) ? MEMZONE_XEN : \ (flsl(mfn_x(page_to_mfn(pg))) ? : 1)) @@ -2336,8 +2336,9 @@ 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(bits_to_zone(bits), zone_hi); + ASSERT(zone_hi != 0); if ( memflags & MEMF_no_owner ) memflags |= MEMF_no_refcount;