From patchwork Wed Oct 2 17:16:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Xia, Hongyan" X-Patchwork-Id: 11171701 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 AC19F14DB for ; Wed, 2 Oct 2019 17:18:37 +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 7D12021D81 for ; Wed, 2 Oct 2019 17:18:37 +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="l3n6Vk/u" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D12021D81 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 1iFiFP-0008D6-KG; Wed, 02 Oct 2019 17:17:07 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iFiFO-0008D1-SO for xen-devel@lists.xenproject.org; Wed, 02 Oct 2019 17:17:06 +0000 X-Inumbo-ID: 730dd424-e538-11e9-bf31-bc764e2007e4 Received: from smtp-fw-4101.amazon.com (unknown [72.21.198.25]) by localhost (Halon) with ESMTPS id 730dd424-e538-11e9-bf31-bc764e2007e4; Wed, 02 Oct 2019 17:17:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1570036622; x=1601572622; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=nPtaka/gXfugAqPQq4HcFHXTvUe4DdTjNQEPXGjd+9c=; b=l3n6Vk/uRuif2X5agAEVXNZnWOKiL9ZaCmJk9+m2U6qQDqGcZf/uKZmc 3S2Rp5NDHzCjf8/0sEMEWsQRdwV2alSDLH3W3BCAvALDwsOcIFM7UCvtP WqSOJjCWUMou2dMPXi9Ci7Qs7/u0LFEwwuHZwvBLHXvp/FR6GOMnzZyS2 4=; X-IronPort-AV: E=Sophos;i="5.67,249,1566864000"; d="scan'208";a="789153766" Received: from iad6-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2a-1c1b5cdd.us-west-2.amazon.com) ([10.124.125.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 02 Oct 2019 17:17:00 +0000 Received: from EX13MTAUEA001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2a-1c1b5cdd.us-west-2.amazon.com (Postfix) with ESMTPS id 8A3FBA1E0F; Wed, 2 Oct 2019 17:16:59 +0000 (UTC) Received: from EX13D06UEE004.ant.amazon.com (10.43.62.44) by EX13MTAUEA001.ant.amazon.com (10.43.61.82) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 2 Oct 2019 17:16:59 +0000 Received: from EX13MTAUEE001.ant.amazon.com (10.43.62.200) by EX13D06UEE004.ant.amazon.com (10.43.62.44) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Wed, 2 Oct 2019 17:16:58 +0000 Received: from u9d785c4ba99158.ant.amazon.com (10.125.106.78) by mail-relay.amazon.com (10.43.62.226) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Wed, 2 Oct 2019 17:16:58 +0000 From: Hongyan Xia To: Date: Wed, 2 Oct 2019 18:16:48 +0100 Message-ID: X-Mailer: git-send-email 2.17.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [PATCH v3 3/9] 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 Reviewed-by: Jan Beulich --- 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 88a15ecdf2..23066c492e 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 ) {