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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E111DC001DF for ; Fri, 20 Oct 2023 15:13:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=DN5UUY6fteRlYcVR/WWHVVeo5t0asjQdSGiwqrkX0PM=; b=UhIl9+kCRFKpf8 UCrt9EWgw2DoSZxVFGDIIFQ54WVcPAhs5CTWikVIonRG8G6tvaNyXoBSCWzJg9n8lmEtPsQZRz4E1 jjgiZo8No6lhqn455qyNjK5njeYniNn6XuBl3wpOaJJa2Rzgm9XKTOYtAeSD6yHZXe9EtbgDszt/M padII2nIxvy0/cwOb3J9JSLbBL6+BUKp9uA7dXhSm6dpIeQoIclplFoX5rB68aUgUY08kWE44Oead 0EXKrzKShVEFAWND/xHcNybj2S7TW2HEvoNvFTqcAxUwKfReY5y3blDUTxMeSFuauKYjkS6AkqRAX RHq5lPioNgGqmXQkBJkQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qtrBZ-002Zo9-2u; Fri, 20 Oct 2023 15:13:13 +0000 Received: from mgamail.intel.com ([134.134.136.20]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qtrBT-002ZXC-1h for kexec@lists.infradead.org; Fri, 20 Oct 2023 15:13:10 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1697814787; x=1729350787; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=FQt/ElawTffVXHEXsjLO8M8ZAD2Dp5CO9gICUmaNuMQ=; b=BMIoxuT4m+W9uESYQRwwLThdGty7pNlkCDt1deBTXSsXkd1DGmPcjDRE iixpUovMnWB7lJbG3bp4Z8YZLN6l9Pw5uTTDT2qNVUdbLgTc2/CMRcVWl aFVbr4y/9XAaGQeIEKV67qIYsgdhlQKBigrWS2kcLfJS1jPSAWlRnNhPZ /glfgGBsUNXGdh5EUXYmycQOflZa1WrV+NFJpbNbGufBF52pURgWwn9x3 p2eIEYy5rzOVGoKAbvijxVJUwdpCOXdbkw8udHQVCvok5n0yup21+iYRc QJm6dg5kLH1nugTmYuwSbxh3ptAhQ0Jz3tVz8H/Y5cbpmSwUrNFCni3nd g==; X-IronPort-AV: E=McAfee;i="6600,9927,10869"; a="376893693" X-IronPort-AV: E=Sophos;i="6.03,239,1694761200"; d="scan'208";a="376893693" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Oct 2023 08:13:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10869"; a="761080289" X-IronPort-AV: E=Sophos;i="6.03,239,1694761200"; d="scan'208";a="761080289" Received: from dgutows1-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.249.39.237]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Oct 2023 08:12:56 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 3BB5B10A29A; Fri, 20 Oct 2023 18:12:45 +0300 (+03) From: "Kirill A. Shutemov" To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: "Rafael J. Wysocki" , Peter Zijlstra , Adrian Hunter , Kuppuswamy Sathyanarayanan , Elena Reshetova , Jun Nakajima , Rick Edgecombe , Tom Lendacky , "Kalra, Ashish" , Sean Christopherson , "Huang, Kai" , Baoquan He , kexec@lists.infradead.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv2 08/13] x86/tdx: Account shared memory Date: Fri, 20 Oct 2023 18:12:37 +0300 Message-ID: <20231020151242.1814-9-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231020151242.1814-1-kirill.shutemov@linux.intel.com> References: <20231020151242.1814-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231020_081307_823256_24C4775C X-CRM114-Status: GOOD ( 16.63 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org The kernel will convert all shared memory back to private during kexec. The direct mapping page tables will provide information on which memory is shared. It is extremely important to convert all shared memory. If a page is missed, it will cause the second kernel to crash when it accesses it. Keep track of the number of shared pages. This will allow for cross-checking against the shared information in the direct mapping and reporting if the shared bit is lost. Include a debugfs interface that allows for the check to be performed at any point. Signed-off-by: Kirill A. Shutemov --- arch/x86/coco/tdx/tdx.c | 69 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index 8897d3cc8a15..587bdeb88afa 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -5,6 +5,7 @@ #define pr_fmt(fmt) "tdx: " fmt #include +#include #include #include #include @@ -37,6 +38,13 @@ #define TDREPORT_SUBTYPE_0 0 +static atomic_long_t nr_shared; + +static inline bool pte_decrypted(pte_t pte) +{ + return cc_mkdec(pte_val(pte)) == pte_val(pte); +} + /* Called from __tdx_hypercall() for unrecoverable failure */ noinstr void __noreturn __tdx_hypercall_failed(void) { @@ -799,6 +807,11 @@ static int tdx_enc_status_change_finish(unsigned long vaddr, int numpages, if (!enc && !tdx_enc_status_changed(vaddr, numpages, enc)) return -EIO; + if (enc) + atomic_long_sub(numpages, &nr_shared); + else + atomic_long_add(numpages, &nr_shared); + return 0; } @@ -874,3 +887,59 @@ void __init tdx_early_init(void) pr_info("Guest detected\n"); } + +#ifdef CONFIG_DEBUG_FS +static int tdx_shared_memory_show(struct seq_file *m, void *p) +{ + unsigned long addr, end; + unsigned long found = 0; + + addr = PAGE_OFFSET; + end = PAGE_OFFSET + get_max_mapped(); + + while (addr < end) { + unsigned long size; + unsigned int level; + pte_t *pte; + + pte = lookup_address(addr, &level); + size = page_level_size(level); + + if (pte && pte_decrypted(*pte)) + found += size / PAGE_SIZE; + + addr += size; + + cond_resched(); + } + + seq_printf(m, "Number of unshared pages in kernel page tables: %16lu\n", + found); + seq_printf(m, "Number of pages accounted as unshared: %16ld\n", + atomic_long_read(&nr_shared)); + return 0; +} + +static int tdx_shared_memory_open(struct inode *inode, struct file *file) +{ + return single_open(file, tdx_shared_memory_show, NULL); +} + +static const struct file_operations tdx_shared_memory_fops = { + .open = tdx_shared_memory_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static __init int debug_tdx_shared_memory(void) +{ + if (!cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) + return 0; + + debugfs_create_file("tdx_shared_memory", S_IRUSR, arch_debugfs_dir, + NULL, &tdx_shared_memory_fops); + return 0; +} +fs_initcall(debug_tdx_shared_memory); +#endif -- 2.41.0 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec