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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3447C4338F for ; Thu, 5 Aug 2021 00:55:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E000B600CD for ; Thu, 5 Aug 2021 00:55:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236791AbhHEA4H (ORCPT ); Wed, 4 Aug 2021 20:56:07 -0400 Received: from mga09.intel.com ([134.134.136.24]:27469 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237465AbhHEAy6 (ORCPT ); Wed, 4 Aug 2021 20:54:58 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10066"; a="214027500" X-IronPort-AV: E=Sophos;i="5.84,296,1620716400"; d="scan'208";a="214027500" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2021 17:53:53 -0700 X-IronPort-AV: E=Sophos;i="5.84,296,1620716400"; d="scan'208";a="437617307" Received: from mjkendri-mobl.amr.corp.intel.com (HELO skuppusw-desk1.amr.corp.intel.com) ([10.254.17.117]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2021 17:53:51 -0700 From: Kuppuswamy Sathyanarayanan To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Peter Zijlstra , Andy Lutomirski , Bjorn Helgaas , Richard Henderson , Thomas Bogendoerfer , James E J Bottomley , Helge Deller , "David S . Miller" , Arnd Bergmann , Jonathan Corbet , "Michael S . Tsirkin" Cc: Peter H Anvin , Dave Hansen , Tony Luck , Dan Williams , Andi Kleen , Kirill Shutemov , Sean Christopherson , Kuppuswamy Sathyanarayanan , x86@kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-alpha@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH v4 15/15] x86/tdx: Add cmdline option to force use of ioremap_shared Date: Wed, 4 Aug 2021 17:52:18 -0700 Message-Id: <20210805005218.2912076-16-sathyanarayanan.kuppuswamy@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210805005218.2912076-1-sathyanarayanan.kuppuswamy@linux.intel.com> References: <20210805005218.2912076-1-sathyanarayanan.kuppuswamy@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a command line option to force all the enabled drivers to use shared memory mappings. This will be useful when enabling new drivers in the protected guest without making all the required changes to use shared mappings in it. Note that this might also allow other non explicitly enabled drivers to interact with the host, which could cause other security risks. Signed-off-by: Kuppuswamy Sathyanarayanan --- .../admin-guide/kernel-parameters.rst | 1 + .../admin-guide/kernel-parameters.txt | 12 ++++++++++++ arch/x86/include/asm/io.h | 2 ++ arch/x86/mm/ioremap.c | 19 ++++++++++++++++++- 4 files changed, 33 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.rst b/Documentation/admin-guide/kernel-parameters.rst index 01ba293a2d70..bdf3896a100c 100644 --- a/Documentation/admin-guide/kernel-parameters.rst +++ b/Documentation/admin-guide/kernel-parameters.rst @@ -147,6 +147,7 @@ parameter is applicable:: PCI PCI bus support is enabled. PCIE PCI Express support is enabled. PCMCIA The PCMCIA subsystem is enabled. + PG Protected guest is enabled. PNP Plug & Play support is enabled. PPC PowerPC architecture is enabled. PPT Parallel port support is enabled. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index bdb22006f713..ba390be62f89 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2062,6 +2062,18 @@ 1 - Bypass the IOMMU for DMA. unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH. + ioremap_force_shared= [X86_64, PG] + Force the kernel to use shared memory mappings which do + not use ioremap_shared/pcimap_shared to opt-in to shared + mappings with the host. This feature is mainly used by + a protected guest when enabling new drivers without + proper shared memory related changes. Please note that + this option might also allow other non explicitly enabled + drivers to interact with the host in protected guest, + which could cause other security risks. This option will + also cause BIOS data structures to be shared with the host, + which might open security holes. + io7= [HW] IO7 for Marvel-based Alpha systems See comment before marvel_specify_io7 in arch/alpha/kernel/core_marvel.c. diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 51c2c45456bf..744f72835a30 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -413,6 +413,8 @@ extern bool arch_memremap_can_ram_remap(resource_size_t offset, extern bool phys_mem_access_encrypted(unsigned long phys_addr, unsigned long size); +extern bool ioremap_force_shared; + /** * iosubmit_cmds512 - copy data to single MMIO location, in 512-bit units * @dst: destination, in MMIO space (must be 512-bit aligned) diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 74260aaa494b..7576e886fad8 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -28,6 +28,7 @@ #include #include #include +#include #include "physaddr.h" @@ -162,6 +163,17 @@ static void __ioremap_check_mem(resource_size_t addr, unsigned long size, __ioremap_check_other(addr, desc); } +/* + * Normally only drivers that are hardened for use in confidential guests + * force shared mappings. But if device filtering is disabled other + * devices can be loaded, and these need shared mappings too. This + * variable is set to true if these filters are disabled. + * + * Note this has some side effects, e.g. various BIOS tables + * get shared too which is risky. + */ +bool ioremap_force_shared; + /* * Remap an arbitrary physical address space into the kernel virtual * address space. It transparently creates kernel huge I/O mapping when @@ -249,7 +261,7 @@ __ioremap_caller(resource_size_t phys_addr, unsigned long size, prot = PAGE_KERNEL_IO; if ((io_desc.flags & IORES_MAP_ENCRYPTED) || encrypted) prot = pgprot_encrypted(prot); - else if (shared) + else if (shared || ioremap_force_shared) prot = pgprot_protected_guest(prot); switch (pcm) { @@ -847,6 +859,11 @@ void __init early_ioremap_init(void) WARN_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1)); #endif + /* Parse cmdline params for ioremap_force_shared */ + if (cmdline_find_option_bool(boot_command_line, + "ioremap_force_shared")) + ioremap_force_shared = 1; + early_ioremap_setup(); pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)); -- 2.25.1