From patchwork Tue Jan 7 12:06:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Xia, Hongyan" X-Patchwork-Id: 11320821 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 33686930 for ; Tue, 7 Jan 2020 12:08:17 +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 103E7206F0 for ; Tue, 7 Jan 2020 12:08:16 +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="ASjzOJS9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 103E7206F0 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 1iondf-0004vH-MD; Tue, 07 Jan 2020 12:07:11 +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 1ionde-0004ut-Kt for xen-devel@lists.xenproject.org; Tue, 07 Jan 2020 12:07:10 +0000 X-Inumbo-ID: 3a4b5878-3146-11ea-abea-12813bfff9fa Received: from smtp-fw-6002.amazon.com (unknown [52.95.49.90]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 3a4b5878-3146-11ea-abea-12813bfff9fa; Tue, 07 Jan 2020 12:07:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1578398828; x=1609934828; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=+zVQP4wvGmxUJMXWIxCOYEmPNTxv3X5lBU4BlGgepwY=; b=ASjzOJS9dVbjneQaL9wMhNuLoZ+ZuJfjN55fsMG3qPMRu0mXvKOIagMn cBcPZhehGS0FkNAdEXns+HwoUkg3fjc4XFNc0FQ54gJK7XgmmpB32uA+j 1xQLrGQ4FsRqAfrU+HJ4jHjn9zCTGZp+83B25xab4vXNFZbc28Zs0uAQZ M=; IronPort-SDR: vaOeRBeSB5BFjpVEYyPXEgfBVpZzqtv6YVbB6ZOg4GBRoGhEXc3ICJsYfgz17GFA0y5btvbON4 idk4iNhA2xJQ== X-IronPort-AV: E=Sophos;i="5.69,406,1571702400"; d="scan'208";a="10390311" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2a-90c42d1d.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-6002.iad6.amazon.com with ESMTP; 07 Jan 2020 12:07:07 +0000 Received: from EX13MTAUEA002.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan3.pdx.amazon.com [10.170.41.166]) by email-inbound-relay-2a-90c42d1d.us-west-2.amazon.com (Postfix) with ESMTPS id 6AC49A1E63; Tue, 7 Jan 2020 12:07:06 +0000 (UTC) Received: from EX13D37EUA003.ant.amazon.com (10.43.165.7) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1236.3; Tue, 7 Jan 2020 12:07:05 +0000 Received: from EX13MTAUWB001.ant.amazon.com (10.43.161.207) by EX13D37EUA003.ant.amazon.com (10.43.165.7) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Tue, 7 Jan 2020 12:07:05 +0000 Received: from u0b3720fa96e858.ant.amazon.com (10.125.106.133) by mail-relay.amazon.com (10.43.161.249) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Tue, 7 Jan 2020 12:07:02 +0000 From: Hongyan Xia To: Date: Tue, 7 Jan 2020 12:06:46 +0000 Message-ID: X-Mailer: git-send-email 2.17.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [PATCH v5 4/7] x86/mm: introduce l{1, 2}t local variables to modify_xen_mappings 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: Wei Liu , Wei Liu , Andrew Cooper , jgrall@amazon.com, Jan Beulich , =?utf-8?q?Roger_Pau_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 | 68 +++++++++++++++++++++++++++++++------------------------ 1 file changed, 38 insertions(+), 30 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index 699aa6bbdf..7160ddcb67 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -5575,6 +5575,8 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) if ( l3e_get_flags(*pl3e) & _PAGE_PSE ) { + l2_pgentry_t *l2t; + if ( l2_table_offset(v) == 0 && l1_table_offset(v) == 0 && ((e - v) >= (1UL << L3_PAGETABLE_SHIFT)) ) @@ -5590,11 +5592,11 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) } /* PAGE1GB: shatter the superpage and fall through. */ - pl2e = alloc_xen_pagetable(); - if ( !pl2e ) + l2t = alloc_xen_pagetable(); + if ( !l2t ) return -ENOMEM; for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ ) - l2e_write(pl2e + i, + l2e_write(l2t + i, l2e_from_pfn(l3e_get_pfn(*pl3e) + (i << PAGETABLE_ORDER), l3e_get_flags(*pl3e))); @@ -5603,14 +5605,14 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) 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); - if ( pl2e ) - free_xen_pagetable(pl2e); + if ( l2t ) + free_xen_pagetable(l2t); } /* @@ -5644,12 +5646,14 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) } else { + l1_pgentry_t *l1t; + /* PSE: shatter the superpage and try again. */ - pl1e = alloc_xen_pagetable(); - if ( !pl1e ) + l1t = alloc_xen_pagetable(); + if ( !l1t ) 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, l2e_get_flags(*pl2e) & ~_PAGE_PSE)); if ( locking ) @@ -5657,19 +5661,19 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) 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); - if ( pl1e ) - free_xen_pagetable(pl1e); + if ( l1t ) + free_xen_pagetable(l1t); } } else { - l1_pgentry_t nl1e; + l1_pgentry_t nl1e, *l1t; /* * Ordinary 4kB mapping: The L2 entry has been verified to be @@ -5716,9 +5720,9 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) continue; } - pl1e = l2e_to_l1e(*pl2e); + l1t = l2e_to_l1e(*pl2e); for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ ) - if ( l1e_get_intpte(pl1e[i]) != 0 ) + if ( l1e_get_intpte(l1t[i]) != 0 ) break; if ( i == L1_PAGETABLE_ENTRIES ) { @@ -5727,7 +5731,7 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) if ( locking ) spin_unlock(&map_pgdir_lock); flush_area(NULL, FLUSH_TLB_GLOBAL); /* flush before free */ - free_xen_pagetable(pl1e); + free_xen_pagetable(l1t); } else if ( locking ) spin_unlock(&map_pgdir_lock); @@ -5756,21 +5760,25 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) continue; } - pl2e = l3e_to_l2e(*pl3e); - for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ ) - if ( l2e_get_intpte(pl2e[i]) != 0 ) - break; - if ( i == L2_PAGETABLE_ENTRIES ) { - /* Empty: zap the L3E and free the L2 page. */ - l3e_write_atomic(pl3e, l3e_empty()); - if ( locking ) + l2_pgentry_t *l2t; + + l2t = l3e_to_l2e(*pl3e); + for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ ) + if ( l2e_get_intpte(l2t[i]) != 0 ) + break; + if ( i == L2_PAGETABLE_ENTRIES ) + { + /* Empty: zap the L3E and free the L2 page. */ + l3e_write_atomic(pl3e, l3e_empty()); + if ( locking ) + spin_unlock(&map_pgdir_lock); + flush_area(NULL, FLUSH_TLB_GLOBAL); /* flush before free */ + free_xen_pagetable(l2t); + } + else if ( locking ) spin_unlock(&map_pgdir_lock); - flush_area(NULL, FLUSH_TLB_GLOBAL); /* flush before free */ - free_xen_pagetable(pl2e); } - else if ( locking ) - spin_unlock(&map_pgdir_lock); } flush_area(NULL, FLUSH_TLB_GLOBAL);