From patchwork Thu Sep 26 09:45:27 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Xia, Hongyan" X-Patchwork-Id: 11162049 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 882A5924 for ; Thu, 26 Sep 2019 09:48:36 +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 5841B222C0 for ; Thu, 26 Sep 2019 09:48:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="IazlgGnw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5841B222C0 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=none 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 1iDQMd-0003cX-8n; Thu, 26 Sep 2019 09:47:07 +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 4.89) (envelope-from ) id 1iDQMb-0003bg-JP for xen-devel@lists.xenproject.org; Thu, 26 Sep 2019 09:47:05 +0000 X-Inumbo-ID: 98f1bd54-e042-11e9-964c-12813bfff9fa Received: from smtp-fw-2101.amazon.com (unknown [72.21.196.25]) by localhost (Halon) with ESMTPS id 98f1bd54-e042-11e9-964c-12813bfff9fa; Thu, 26 Sep 2019 09:47:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1569491224; x=1601027224; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=IwBygj+RhjB/roSYIAno5ZW1vZEaPnrSx3ay7bN2WgM=; b=IazlgGnw7nOwXEWfUhNyLxqwrBlLENHgv6ZMLvVsLvyfGpwHp5ZKzHpn Eew8Stb2YZk/EFr+Osdl3NTntwhtLlrUs1aAhRhZ4ur5+gZiP+beOMgSj +Zir9iRasy0o+Cg5nZr1+4xRZ/wjVOV4rR6MtqGsCB86JZES28VhbDyh5 U=; X-IronPort-AV: E=Sophos;i="5.64,551,1559520000"; d="scan'208";a="753353976" Received: from iad6-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-1e-57e1d233.us-east-1.amazon.com) ([10.124.125.2]) by smtp-border-fw-out-2101.iad2.amazon.com with ESMTP; 26 Sep 2019 09:47:03 +0000 Received: from EX13MTAUWA001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1e-57e1d233.us-east-1.amazon.com (Postfix) with ESMTPS id 7092F141773; Thu, 26 Sep 2019 09:47:01 +0000 (UTC) Received: from EX13D13UWA001.ant.amazon.com (10.43.160.136) by EX13MTAUWA001.ant.amazon.com (10.43.160.118) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Thu, 26 Sep 2019 09:47:01 +0000 Received: from EX13MTAUWA001.ant.amazon.com (10.43.160.58) by EX13D13UWA001.ant.amazon.com (10.43.160.136) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Thu, 26 Sep 2019 09:47:00 +0000 Received: from u9d785c4ba99158.ant.amazon.com (10.125.106.58) by mail-relay.amazon.com (10.43.160.118) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Thu, 26 Sep 2019 09:46:59 +0000 From: To: Date: Thu, 26 Sep 2019 10:45:27 +0100 Message-ID: <57342866b36c4c5184a4e378f1993e985c6c3115.1569489002.git.hongyax@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [RFC PATCH 04/84] x86/mm: introduce l{1, 2}t local variables to map_pages_to_xen X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Andrew Cooper , Wei Liu , 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 The pl2e and pl1e variables are heavily (ab)used in that function. It is fine at the moment because all page tables are always mapped so there is no need to track the life time of each variable. We will soon have the requirement to map and unmap page tables. We need to track the life time of each variable to avoid leakage. Introduce some l{1,2}t variables with limited scope so that we can track life time of pointers to xen page tables more easily. No functional change. Signed-off-by: Wei Liu --- xen/arch/x86/mm.c | 75 ++++++++++++++++++++++++++--------------------- 1 file changed, 42 insertions(+), 33 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index e2c8c3f3a1..2ae8a7736f 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -5061,10 +5061,12 @@ int map_pages_to_xen( } else { - pl2e = l3e_to_l2e(ol3e); + l2_pgentry_t *l2t; + + l2t = l3e_to_l2e(ol3e); for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ ) { - ol2e = pl2e[i]; + ol2e = l2t[i]; if ( !(l2e_get_flags(ol2e) & _PAGE_PRESENT) ) continue; if ( l2e_get_flags(ol2e) & _PAGE_PSE ) @@ -5072,21 +5074,22 @@ int map_pages_to_xen( else { unsigned int j; + l1_pgentry_t *l1t; - pl1e = l2e_to_l1e(ol2e); + l1t = l2e_to_l1e(ol2e); for ( j = 0; j < L1_PAGETABLE_ENTRIES; j++ ) - flush_flags(l1e_get_flags(pl1e[j])); + flush_flags(l1e_get_flags(l1t[j])); } } flush_area(virt, flush_flags); for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ ) { - ol2e = pl2e[i]; + ol2e = l2t[i]; if ( (l2e_get_flags(ol2e) & _PAGE_PRESENT) && !(l2e_get_flags(ol2e) & _PAGE_PSE) ) free_xen_pagetable(l2e_to_l1e(ol2e)); } - free_xen_pagetable(pl2e); + free_xen_pagetable(l2t); } } @@ -5102,6 +5105,7 @@ int map_pages_to_xen( { unsigned int flush_flags = FLUSH_TLB | FLUSH_ORDER(2 * PAGETABLE_ORDER); + l2_pgentry_t *l2t; /* Skip this PTE if there is no change. */ if ( ((l3e_get_pfn(ol3e) & ~(L2_PAGETABLE_ENTRIES * @@ -5123,12 +5127,12 @@ int map_pages_to_xen( continue; } - pl2e = alloc_xen_pagetable(); - if ( pl2e == NULL ) + l2t = alloc_xen_pagetable(); + if ( l2t == NULL ) return -ENOMEM; for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ ) - l2e_write(pl2e + i, + l2e_write(l2t + i, l2e_from_pfn(l3e_get_pfn(ol3e) + (i << PAGETABLE_ORDER), l3e_get_flags(ol3e))); @@ -5141,15 +5145,15 @@ int map_pages_to_xen( if ( (l3e_get_flags(*pl3e) & _PAGE_PRESENT) && (l3e_get_flags(*pl3e) & _PAGE_PSE) ) { - l3e_write_atomic(pl3e, l3e_from_mfn(virt_to_mfn(pl2e), + l3e_write_atomic(pl3e, l3e_from_mfn(virt_to_mfn(l2t), __PAGE_HYPERVISOR)); - pl2e = NULL; + l2t = NULL; } if ( locking ) spin_unlock(&map_pgdir_lock); flush_area(virt, flush_flags); - if ( pl2e ) - free_xen_pagetable(pl2e); + if ( l2t ) + free_xen_pagetable(l2t); } pl2e = virt_to_xen_l2e(virt); @@ -5177,11 +5181,13 @@ int map_pages_to_xen( } else { - pl1e = l2e_to_l1e(ol2e); + l1_pgentry_t *l1t; + + l1t = l2e_to_l1e(ol2e); for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ ) - flush_flags(l1e_get_flags(pl1e[i])); + flush_flags(l1e_get_flags(l1t[i])); flush_area(virt, flush_flags); - free_xen_pagetable(pl1e); + free_xen_pagetable(l1t); } } @@ -5203,6 +5209,7 @@ int map_pages_to_xen( { unsigned int flush_flags = FLUSH_TLB | FLUSH_ORDER(PAGETABLE_ORDER); + l1_pgentry_t *l1t; /* Skip this PTE if there is no change. */ if ( (((l2e_get_pfn(*pl2e) & ~(L1_PAGETABLE_ENTRIES - 1)) + @@ -5222,12 +5229,12 @@ int map_pages_to_xen( goto check_l3; } - pl1e = alloc_xen_pagetable(); - if ( pl1e == NULL ) + l1t = alloc_xen_pagetable(); + if ( l1t == NULL ) return -ENOMEM; for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ ) - l1e_write(&pl1e[i], + l1e_write(&l1t[i], l1e_from_pfn(l2e_get_pfn(*pl2e) + i, lNf_to_l1f(l2e_get_flags(*pl2e)))); @@ -5239,15 +5246,15 @@ int map_pages_to_xen( if ( (l2e_get_flags(*pl2e) & _PAGE_PRESENT) && (l2e_get_flags(*pl2e) & _PAGE_PSE) ) { - l2e_write_atomic(pl2e, l2e_from_mfn(virt_to_mfn(pl1e), + l2e_write_atomic(pl2e, l2e_from_mfn(virt_to_mfn(l1t), __PAGE_HYPERVISOR)); - pl1e = NULL; + l1t = NULL; } if ( locking ) spin_unlock(&map_pgdir_lock); flush_area(virt, flush_flags); - if ( pl1e ) - free_xen_pagetable(pl1e); + if ( l1t ) + free_xen_pagetable(l1t); } pl1e = l2e_to_l1e(*pl2e) + l1_table_offset(virt); @@ -5272,6 +5279,7 @@ int map_pages_to_xen( ((1u << PAGETABLE_ORDER) - 1)) == 0)) ) { unsigned long base_mfn; + l1_pgentry_t *l1t; if ( locking ) spin_lock(&map_pgdir_lock); @@ -5295,11 +5303,11 @@ int map_pages_to_xen( goto check_l3; } - pl1e = l2e_to_l1e(ol2e); - base_mfn = l1e_get_pfn(*pl1e) & ~(L1_PAGETABLE_ENTRIES - 1); - for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++, pl1e++ ) - if ( (l1e_get_pfn(*pl1e) != (base_mfn + i)) || - (l1e_get_flags(*pl1e) != flags) ) + l1t = l2e_to_l1e(ol2e); + base_mfn = l1e_get_pfn(l1t[0]) & ~(L1_PAGETABLE_ENTRIES - 1); + for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ ) + if ( (l1e_get_pfn(l1t[i]) != (base_mfn + i)) || + (l1e_get_flags(l1t[i]) != flags) ) break; if ( i == L1_PAGETABLE_ENTRIES ) { @@ -5325,6 +5333,7 @@ int map_pages_to_xen( ((1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT)) - 1))) ) { unsigned long base_mfn; + l2_pgentry_t *l2t; if ( locking ) spin_lock(&map_pgdir_lock); @@ -5342,13 +5351,13 @@ int map_pages_to_xen( continue; } - pl2e = l3e_to_l2e(ol3e); - base_mfn = l2e_get_pfn(*pl2e) & ~(L2_PAGETABLE_ENTRIES * + l2t = l3e_to_l2e(ol3e); + base_mfn = l2e_get_pfn(l2t[0]) & ~(L2_PAGETABLE_ENTRIES * L1_PAGETABLE_ENTRIES - 1); - for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++, pl2e++ ) - if ( (l2e_get_pfn(*pl2e) != + for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ ) + if ( (l2e_get_pfn(l2t[i]) != (base_mfn + (i << PAGETABLE_ORDER))) || - (l2e_get_flags(*pl2e) != l1f_to_lNf(flags)) ) + (l2e_get_flags(l2t[i]) != l1f_to_lNf(flags)) ) break; if ( i == L2_PAGETABLE_ENTRIES ) {