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Shutemov" X-Patchwork-Id: 11068157 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1FD4013A4 for ; Wed, 31 Jul 2019 15:10:41 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0AFEB201F5 for ; Wed, 31 Jul 2019 15:10:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F313B1FF14; Wed, 31 Jul 2019 15:10:40 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=unavailable version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2A11620243 for ; Wed, 31 Jul 2019 15:10:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 481A78E001E; Wed, 31 Jul 2019 11:10:39 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 432318E0005; Wed, 31 Jul 2019 11:10:39 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2D2758E001E; Wed, 31 Jul 2019 11:10:39 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id CF5178E0005 for ; Wed, 31 Jul 2019 11:10:38 -0400 (EDT) Received: by mail-ed1-f72.google.com with SMTP id o13so42620463edt.4 for ; Wed, 31 Jul 2019 08:10:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:from:to:cc:subject:date :message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=lUZ5o3KyzJhrWdCGYLPb2yVyWjyFss5E3sxw1k1xFj4=; b=cOQkMff9Ix1gaRx8WfaGj3a6t2FX6lZI7mcWA7bVuXcM+VyiRQ9+m/+UBZXVHZ/Nkt ddAy1nznzzUW7dl3iXehtfsFUgY+84UMvDTHkZpthpF03A+OJYfbNlFmiFJ990zee+5R dEL7ujSSszz2gGtCyF0hnZjyWawe7aDH/do6DMWribxxq54f/mG5BArnKk5x7dberrQA 1Pk8jG+Oe/5si9/VmkbbeAyvigJh8SCRE69Z6b/vIXhDe5lIAAerXkuW8wRN07lVQag5 ziSEoWwHGBkl52zDeYi8v2KaUPSrIpDlrb0NzL2cGQoMY1tvUEAfbEeCCw8tetkB13Ho DLQg== X-Gm-Message-State: APjAAAWIrViL19XTpMYHq1hr2LssfUn1ZW0LZlmOV3DFRtS8lqHtwHNF +EMuH2ljonq5YOxjRbyXLykWNVVjeKQCP5FTiDdmtZ9kKCAyeXawD8/IzNfEFuygUmxkvsC/idh wx0GGF7Sg2kr0wMUkFRKeW6WWL82MKlMBbN5DnAYDyOSjsmsZHkDLfet5XDKiwf0= X-Received: by 2002:a17:906:f2d0:: with SMTP id gz16mr2101746ejb.21.1564585838188; Wed, 31 Jul 2019 08:10:38 -0700 (PDT) X-Received: by 2002:a17:906:f2d0:: with SMTP id gz16mr2089966ejb.21.1564585706691; Wed, 31 Jul 2019 08:08:26 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1564585706; cv=none; d=google.com; s=arc-20160816; b=RoUUhQcQJB0YXp95U1+7Pzu+w3zXWz/ls21/PJWQNzYwklRiQ6yrNaiSuNDf8R5oZJ fqrdfLBPO6jBpWOXwRajt9CDPZ1BO8CXDdJVl2aHJ0ked5Ioefu//TkAY8CvOWNij3/Y 2aA4UZs3zmkllreA+3e1rKLJjKtuDWSmhzwtA5MR+Vpdoo6LdKynoELTIieyEhkcZoqO shtjnl64ID9o4n48luxh/eCTJh8p4eZCUdxFqeEGZ3drsnPR8GoRc3pJz9Ynga8pfE1u 8Zcs0d5CEUPdKiO7tDE90DH656SryHe7yocWoMAAF5736xJ2HLB1ssm22EhKXK2aLnSh NGDw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:dkim-signature; bh=lUZ5o3KyzJhrWdCGYLPb2yVyWjyFss5E3sxw1k1xFj4=; b=YDHyDBhZEwWsQyJ+u0xLMJdiTJqTfBGsfhg5Tpb4zrZHYuhPQ7YWWJZeYnARv543OC 14763R3OGHLB0wME6Km/6QnA9JqxqkNFou+Mq3s0pZEZ67UuxvDMB7rrBT1iWRLRFMBl 7FJMaC/KzceUSwsqeDm+uzAaYDqJm99G2lwsyHY8AJmXxrJYCKIJQzuMMfPrGP9veVM2 cWmejI+prEpbp9DAU/REVLG69hpZysvTsCgSHCrlnz7kuw9m9kgCjc8EpWjavCMBjGDi SzJyuSPuqQjGA2RuASCN1HUtepvNQuE8j6BpH7TzOlOi4bEmLWzfH2fT7EvmTPHAjzCO vp5A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@shutemov-name.20150623.gappssmtp.com header.s=20150623 header.b=f87cDXaJ; spf=neutral (google.com: 209.85.220.65 is neither permitted nor denied by best guess record for domain of kirill@shutemov.name) smtp.mailfrom=kirill@shutemov.name Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id e1sor22572743ejc.8.2019.07.31.08.08.26 for (Google Transport Security); Wed, 31 Jul 2019 08:08:26 -0700 (PDT) Received-SPF: neutral (google.com: 209.85.220.65 is neither permitted nor denied by best guess record for domain of kirill@shutemov.name) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@shutemov-name.20150623.gappssmtp.com header.s=20150623 header.b=f87cDXaJ; spf=neutral (google.com: 209.85.220.65 is neither permitted nor denied by best guess record for domain of kirill@shutemov.name) smtp.mailfrom=kirill@shutemov.name DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=lUZ5o3KyzJhrWdCGYLPb2yVyWjyFss5E3sxw1k1xFj4=; b=f87cDXaJ8tGVJamu+eP2PyzCUG+ZqKOVZGcAGMCXDWHjkJRyvJrzvQl3kbA74mRwxX OqfZG5qQ+bo+nU4FmQUQEfW8xtRk3mQqCOhXO4ONCK2ETh94d3kePxhHQni0xuu74lB4 Y20jFqWjk03QJHsbAjUW4+PFAHLmrv0r6qgsbOO6Jd3/C5xW3cbTj34qRDlJTmRtO5jx RWRM2zh83FmKCv2tiLddj/gDtFIbBkm3P+F0EW4xaKzZM7lJSg8hSxUFcFFMufgrsNgt eaUf+JW89LkyPwaNnhVGpOMNBErtkA5zeIGuiR/MLONHF6hagKmRxYvFL5eQn9P8H2G7 0/oQ== X-Google-Smtp-Source: APXvYqwFfmfqoKDjr35+pHqpLUwSHQdO/AlnABQJgMuN58XW0JuVzWoIJ2kNgFPcROx7eyZq64QKqA== X-Received: by 2002:a17:906:489a:: with SMTP id v26mr95592305ejq.234.1564585706213; Wed, 31 Jul 2019 08:08:26 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id b53sm17306948edd.45.2019.07.31.08.08.21 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 31 Jul 2019 08:08:22 -0700 (PDT) From: "Kirill A. Shutemov" X-Google-Original-From: "Kirill A. Shutemov" Received: by box.localdomain (Postfix, from userid 1000) id 6BDC6102993; Wed, 31 Jul 2019 18:08:16 +0300 (+03) To: Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Borislav Petkov , Peter Zijlstra , Andy Lutomirski , David Howells Cc: Kees Cook , Dave Hansen , Kai Huang , Jacob Pan , Alison Schofield , linux-mm@kvack.org, kvm@vger.kernel.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv2 18/59] x86/mm: Calculate direct mapping size Date: Wed, 31 Jul 2019 18:07:32 +0300 Message-Id: <20190731150813.26289-19-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190731150813.26289-1-kirill.shutemov@linux.intel.com> References: <20190731150813.26289-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP The kernel needs to have a way to access encrypted memory. We have two option on how approach it: - Create temporary mappings every time kernel needs access to encrypted memory. That's basically brings highmem and its overhead back. - Create multiple direct mappings, one per-KeyID. In this setup we don't need to create temporary mappings on the fly -- encrypted memory is permanently available in kernel address space. We take the second approach as it has lower overhead. It's worth noting that with per-KeyID direct mappings compromised kernel would give access to decrypted data right away without additional tricks to get memory mapped with the correct KeyID. Per-KeyID mappings require a lot more virtual address space. On 4-level machine with 64 KeyIDs we max out 46-bit virtual address space dedicated for direct mapping with 1TiB of RAM. Given that we round up any calculation on direct mapping size to 1TiB, we effectively claim all 46-bit address space for direct mapping on such machine regardless of RAM size. Increased usage of virtual address space has implications for KASLR: we have less space for randomization. With 64 TiB claimed for direct mapping with 4-level we left with 27 TiB of entropy to place page_offset_base, vmalloc_base and vmemmap_base. 5-level paging provides much wider virtual address space and KASLR doesn't suffer significantly from per-KeyID direct mappings. It's preferred to run MKTME with 5-level paging. A direct mapping for each KeyID will be put next to each other in the virtual address space. We need to have a way to find boundaries of direct mapping for particular KeyID. The new variable direct_mapping_size specifies the size of direct mapping. With the value, it's trivial to find direct mapping for KeyID-N: PAGE_OFFSET + N * direct_mapping_size. Size of direct mapping is calculated during KASLR setup. If KALSR is disabled it happens during MKTME initialization. With MKTME size of direct mapping has to be power-of-2. It makes implementation of __pa() efficient. Signed-off-by: Kirill A. Shutemov --- Documentation/x86/x86_64/mm.rst | 4 +++ arch/x86/include/asm/page_32.h | 1 + arch/x86/include/asm/page_64.h | 2 ++ arch/x86/include/asm/setup.h | 6 ++++ arch/x86/kernel/head64.c | 4 +++ arch/x86/kernel/setup.c | 3 ++ arch/x86/mm/init_64.c | 58 +++++++++++++++++++++++++++++++++ arch/x86/mm/kaslr.c | 11 +++++-- 8 files changed, 86 insertions(+), 3 deletions(-) diff --git a/Documentation/x86/x86_64/mm.rst b/Documentation/x86/x86_64/mm.rst index 267fc4808945..7978afe6c396 100644 --- a/Documentation/x86/x86_64/mm.rst +++ b/Documentation/x86/x86_64/mm.rst @@ -140,6 +140,10 @@ The direct mapping covers all memory in the system up to the highest memory address (this means in some cases it can also include PCI memory holes). +With MKTME, we have multiple direct mappings. One per-KeyID. They are put +next to each other. PAGE_OFFSET + N * direct_mapping_size can be used to +find direct mapping for KeyID-N. + vmalloc space is lazily synchronized into the different PML4/PML5 pages of the processes using the page fault handler, with init_top_pgt as reference. diff --git a/arch/x86/include/asm/page_32.h b/arch/x86/include/asm/page_32.h index 94dbd51df58f..8bce788f9ca9 100644 --- a/arch/x86/include/asm/page_32.h +++ b/arch/x86/include/asm/page_32.h @@ -6,6 +6,7 @@ #ifndef __ASSEMBLY__ +#define direct_mapping_size 0 #define __phys_addr_nodebug(x) ((x) - PAGE_OFFSET) #ifdef CONFIG_DEBUG_VIRTUAL extern unsigned long __phys_addr(unsigned long); diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h index 939b1cff4a7b..f57fc3cc2246 100644 --- a/arch/x86/include/asm/page_64.h +++ b/arch/x86/include/asm/page_64.h @@ -14,6 +14,8 @@ extern unsigned long phys_base; extern unsigned long page_offset_base; extern unsigned long vmalloc_base; extern unsigned long vmemmap_base; +extern unsigned long direct_mapping_size; +extern unsigned long direct_mapping_mask; static inline unsigned long __phys_addr_nodebug(unsigned long x) { diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h index ed8ec011a9fd..d2861074cf83 100644 --- a/arch/x86/include/asm/setup.h +++ b/arch/x86/include/asm/setup.h @@ -62,6 +62,12 @@ extern void x86_ce4100_early_setup(void); static inline void x86_ce4100_early_setup(void) { } #endif +#ifdef CONFIG_MEMORY_PHYSICAL_PADDING +void calculate_direct_mapping_size(void); +#else +static inline void calculate_direct_mapping_size(void) { } +#endif + #ifndef _SETUP #include diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 29ffa495bd1c..006d3ff46afe 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -60,6 +60,10 @@ EXPORT_SYMBOL(vmalloc_base); unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4; EXPORT_SYMBOL(vmemmap_base); #endif +unsigned long direct_mapping_size __ro_after_init = -1UL; +EXPORT_SYMBOL(direct_mapping_size); +unsigned long direct_mapping_mask __ro_after_init = -1UL; +EXPORT_SYMBOL(direct_mapping_mask); #define __head __section(.head.text) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index bbe35bf879f5..d12431e20876 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1077,6 +1077,9 @@ void __init setup_arch(char **cmdline_p) */ init_cache_modes(); + /* direct_mapping_size has to be initialized before KASLR and MKTME */ + calculate_direct_mapping_size(); + /* * Define random base addresses for memory sections after max_pfn is * defined and before each memory section base is used. diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index a6b5c653727b..4c1f93df47a5 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1440,6 +1440,64 @@ unsigned long memory_block_size_bytes(void) return memory_block_size_probed; } +#ifdef CONFIG_MEMORY_PHYSICAL_PADDING +void __init calculate_direct_mapping_size(void) +{ + unsigned long available_va; + + /* 1/4 of virtual address space is didicated for direct mapping */ + available_va = 1UL << (__VIRTUAL_MASK_SHIFT - 1); + + /* How much memory the system has? */ + direct_mapping_size = max_pfn << PAGE_SHIFT; + direct_mapping_size = round_up(direct_mapping_size, 1UL << 40); + + if (!mktme_nr_keyids()) + goto out; + + /* + * For MKTME we need direct_mapping_size to be power-of-2. + * It makes __pa() implementation efficient. + */ + direct_mapping_size = roundup_pow_of_two(direct_mapping_size); + + /* + * Not enough virtual address space to address all physical memory with + * MKTME enabled. Even without padding. + * + * Disable MKTME instead. + */ + if (direct_mapping_size > available_va / (mktme_nr_keyids() + 1)) { + pr_err("x86/mktme: Disabled. Not enough virtual address space\n"); + pr_err("x86/mktme: Consider switching to 5-level paging\n"); + mktme_disable(); + goto out; + } + + /* + * Virtual address space is divided between per-KeyID direct mappings. + */ + available_va /= mktme_nr_keyids() + 1; +out: + /* Add padding, if there's enough virtual address space */ + direct_mapping_size += (1UL << 40) * CONFIG_MEMORY_PHYSICAL_PADDING; + if (mktme_nr_keyids()) + direct_mapping_size = roundup_pow_of_two(direct_mapping_size); + + if (direct_mapping_size > available_va) + direct_mapping_size = available_va; + + /* + * For MKTME, make sure direct_mapping_size is still power-of-2 + * after adding padding and calculate mask that is used in __pa(). + */ + if (mktme_nr_keyids()) { + direct_mapping_size = rounddown_pow_of_two(direct_mapping_size); + direct_mapping_mask = direct_mapping_size - 1; + } +} +#endif + #ifdef CONFIG_SPARSEMEM_VMEMMAP /* * Initialise the sparsemem vmemmap using huge-pages at the PMD level. diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c index 580b82c2621b..83af41d289ed 100644 --- a/arch/x86/mm/kaslr.c +++ b/arch/x86/mm/kaslr.c @@ -103,10 +103,15 @@ void __init kernel_randomize_memory(void) * add padding if needed (especially for memory hotplug support). */ BUG_ON(kaslr_regions[0].base != &page_offset_base); - memory_tb = DIV_ROUND_UP(max_pfn << PAGE_SHIFT, 1UL << TB_SHIFT) + - CONFIG_MEMORY_PHYSICAL_PADDING; - /* Adapt phyiscal memory region size based on available memory */ + /* + * Calculate space required to map all physical memory. + * In case of MKTME, we map physical memory multiple times, one for + * each KeyID. If MKTME is disabled mktme_nr_keyids() is 0. + */ + memory_tb = (direct_mapping_size * (mktme_nr_keyids() + 1)) >> TB_SHIFT; + + /* Adapt physical memory region size based on available memory */ if (memory_tb < kaslr_regions[0].size_tb) kaslr_regions[0].size_tb = memory_tb;