From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 89AA5C433F5 for ; Fri, 8 Apr 2022 09:12:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233228AbiDHJOp (ORCPT ); Fri, 8 Apr 2022 05:14:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232841AbiDHJLu (ORCPT ); Fri, 8 Apr 2022 05:11:50 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A24941DFDF4; Fri, 8 Apr 2022 02:09:04 -0700 (PDT) Date: Fri, 08 Apr 2022 09:09:02 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1649408943; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SLE/rRva5DLP+aDrv6WhBZoi8F8gBarO4PJbL/K1o3Q=; b=BKAWdoNb3kcpVQv6sUQ+qD4KCd+CQMq2pj/3sU0D6l/GyH6cNKA+Mc8Ti68WTdw3ArH+a3 QkDRlSxEU2qubyf+ddgKgUezcnNn8V+kGx66j4A8omG4oh9gYAsmRFpcLJxYKQqccEKIsY jG2dTJs07O2tEMXoQW2vLjg+9TkQyZjiEBm9rMtAttT5iIdvsWhoARD3tlLMSGNoTY1oWF /eO3Dr40es8suyWvK8eQ8eVIRvoKnbuNwwQ3C/czaUH2E3RWCJwvgVxeMy6CyoalpKfTqY 6iHiT8NBX7EHF/6wfNOP6d3gSrmEFuKBMbPq1/vflun37Pm5+YI0pkV4lgcI9w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1649408943; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SLE/rRva5DLP+aDrv6WhBZoi8F8gBarO4PJbL/K1o3Q=; b=47S25CrqMHfAre8OEYUrWYG2pHfsggadyQyeAW9hz1qB6Hef9ITxjs7f6KMeHeGgZRO3st PbQwFdhZmntE3YBw== From: "tip-bot2 for Brijesh Singh" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/sev] x86/kernel: Validate ROM memory before accessing when SEV-SNP is active Cc: Brijesh Singh , Borislav Petkov , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20220307213356.2797205-21-brijesh.singh@amd.com> References: <20220307213356.2797205-21-brijesh.singh@amd.com> MIME-Version: 1.0 Message-ID: <164940894216.389.2848602772534996789.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/sev branch of tip: Commit-ID: 9704c07bf9f7682a83aec4e66f2d9154dbd8577f Gitweb: https://git.kernel.org/tip/9704c07bf9f7682a83aec4e66f2d9154dbd8577f Author: Brijesh Singh AuthorDate: Wed, 09 Feb 2022 12:10:14 -06:00 Committer: Borislav Petkov CommitterDate: Wed, 06 Apr 2022 13:23:09 +02:00 x86/kernel: Validate ROM memory before accessing when SEV-SNP is active probe_roms() accesses the memory range (0xc0000 - 0x10000) to probe various ROMs. The memory range is not part of the E820 system RAM range. The memory range is mapped as private (i.e encrypted) in the page table. When SEV-SNP is active, all the private memory must be validated before accessing. The ROM range was not part of E820 map, so the guest BIOS did not validate it. An access to invalidated memory will cause a exception yet, so validate the ROM memory regions before it is accessed. [ bp: Massage commit message. ] Signed-off-by: Brijesh Singh Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220307213356.2797205-21-brijesh.singh@amd.com --- arch/x86/kernel/probe_roms.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/probe_roms.c b/arch/x86/kernel/probe_roms.c index 36e84d9..319fef3 100644 --- a/arch/x86/kernel/probe_roms.c +++ b/arch/x86/kernel/probe_roms.c @@ -21,6 +21,7 @@ #include #include #include +#include static struct resource system_rom_resource = { .name = "System ROM", @@ -197,11 +198,21 @@ static int __init romchecksum(const unsigned char *rom, unsigned long length) void __init probe_roms(void) { - const unsigned char *rom; unsigned long start, length, upper; + const unsigned char *rom; unsigned char c; int i; + /* + * The ROM memory range is not part of the e820 table and is therefore not + * pre-validated by BIOS. The kernel page table maps the ROM region as encrypted + * memory, and SNP requires encrypted memory to be validated before access. + * Do that here. + */ + snp_prep_memory(video_rom_resource.start, + ((system_rom_resource.end + 1) - video_rom_resource.start), + SNP_PAGE_STATE_PRIVATE); + /* video rom */ upper = adapter_rom_resources[0].start; for (start = video_rom_resource.start; start < upper; start += 2048) {