From patchwork Fri May 29 11:11:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hongyan Xia X-Patchwork-Id: 11578323 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EA82F912 for ; Fri, 29 May 2020 11:13:11 +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 C6FA8207D4 for ; Fri, 29 May 2020 11:13:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=xen.org header.i=@xen.org header.b="RyNqcxQd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C6FA8207D4 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 localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jecvz-0004mv-NJ; Fri, 29 May 2020 11:12:19 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jecvx-0004me-SZ for xen-devel@lists.xenproject.org; Fri, 29 May 2020 11:12:17 +0000 X-Inumbo-ID: 3fbe03e2-a19d-11ea-9dbe-bc764e2007e4 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 3fbe03e2-a19d-11ea-9dbe-bc764e2007e4; Fri, 29 May 2020 11:12:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Sender:Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=wpKga3yyO5WYBCcsTT/9ZqLEb5cI9pIQiRxp5mp3PjU=; b=RyNqcxQd5F8o0SmM/SdkYCxZ/x /HD7oLZYAEojQE/q/FHNkVirpBbrotQnDPYk2oVVfYNC06Kqto67WzrWaSMf6KUnOqiQ84152Myp+ Ar172xs0z4a8Quc2UZ1w5C3wxWMb1IQqUY0FIVyBg3ROhNs24vlQC0kNkyxXrlXiqkME=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jecvt-00021p-H9; Fri, 29 May 2020 11:12:13 +0000 Received: from 54-240-197-236.amazon.com ([54.240.197.236] helo=u1bbd043a57dd5a.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jecvt-0006tM-79; Fri, 29 May 2020 11:12:13 +0000 From: Hongyan Xia To: xen-devel@lists.xenproject.org Subject: [PATCH v7 02/15] x86/mm: make sure there is one exit path for modify_xen_mappings Date: Fri, 29 May 2020 12:11:46 +0100 Message-Id: <3edeb558a0586cf5ecb235c9159cd00fe1197b9e.1590750232.git.hongyxia@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: 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: Andrew Cooper , julien@xen.org, Wei Liu , Jan Beulich , =?utf-8?q?Roger_Pau_?= =?utf-8?q?Monn=C3=A9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" From: Wei Liu We will soon need to handle dynamically mapping / unmapping page tables in the said function. Since dynamic mappings may map and unmap pl3e in different iterations, lift pl3e out of the loop. No functional change. Signed-off-by: Wei Liu Signed-off-by: Hongyan Xia --- Changed since v4: - drop the end_of_loop goto label. Changed since v3: - remove asserts on rc since it never gets changed to anything else. --- xen/arch/x86/mm.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index d99f9bc133..462682ba70 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -5457,10 +5457,12 @@ int populate_pt_range(unsigned long virt, unsigned long nr_mfns) int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) { bool locking = system_state > SYS_STATE_boot; + l3_pgentry_t *pl3e; l2_pgentry_t *pl2e; l1_pgentry_t *pl1e; unsigned int i; unsigned long v = s; + int rc = -ENOMEM; /* Set of valid PTE bits which may be altered. */ #define FLAGS_MASK (_PAGE_NX|_PAGE_RW|_PAGE_PRESENT) @@ -5471,7 +5473,7 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) while ( v < e ) { - l3_pgentry_t *pl3e = virt_to_xen_l3e(v); + pl3e = virt_to_xen_l3e(v); if ( !pl3e || !(l3e_get_flags(*pl3e) & _PAGE_PRESENT) ) { @@ -5504,7 +5506,8 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) /* PAGE1GB: shatter the superpage and fall through. */ l2t = alloc_xen_pagetable(); if ( !l2t ) - return -ENOMEM; + goto out; + for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ ) l2e_write(l2t + i, l2e_from_pfn(l3e_get_pfn(*pl3e) + @@ -5561,7 +5564,8 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) /* PSE: shatter the superpage and try again. */ l1t = alloc_xen_pagetable(); if ( !l1t ) - return -ENOMEM; + goto out; + for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ ) l1e_write(&l1t[i], l1e_from_pfn(l2e_get_pfn(*pl2e) + i, @@ -5694,7 +5698,10 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) flush_area(NULL, FLUSH_TLB_GLOBAL); #undef FLAGS_MASK - return 0; + rc = 0; + + out: + return rc; } #undef flush_area