From patchwork Mon Nov 21 00:26:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Kai" X-Patchwork-Id: 13050242 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 39E58C4332F for ; Mon, 21 Nov 2022 00:31:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229938AbiKUAbD (ORCPT ); Sun, 20 Nov 2022 19:31:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229929AbiKUAa2 (ORCPT ); Sun, 20 Nov 2022 19:30:28 -0500 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E65991E708; Sun, 20 Nov 2022 16:28:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1668990537; x=1700526537; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=jIBcb5cVMwmxp99dDnDGXF9eYbfG3mWlVut9+yUNmLc=; b=T3Vg7vCuQSdz5CNeHk1ybLQkedvecjgDu3L+33rOOaE5zbN81zHyls4w 0MA6UySZb7sSsoOTizQ1K5mRux81qCxeK2w7PmjjP75Y/lTk0ufiL0u3n 5oNBKyc02m+uPl88OI0g4kuN0eljC7TI1LqU+Rpsi2+gu3ewvg4Kh3uHJ JqnOIlqaiM0KsZzJe6IjNhhfJ1Odw5cWf8pkN2C7Eofb74ihh5ejkoWUV Pe2eStsG3Z4pwxbNBRuatz/am5jBL003yO3nOaw1MT/7IMbgxZTbLOGi4 ibrn2GKqMWx6v6fHsSc1a9OFiQlTzqL9iNhSBmGW+QXlYUkBvlF5jAEdc A==; X-IronPort-AV: E=McAfee;i="6500,9779,10537"; a="377705756" X-IronPort-AV: E=Sophos;i="5.96,180,1665471600"; d="scan'208";a="377705756" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Nov 2022 16:28:09 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10537"; a="729825533" X-IronPort-AV: E=Sophos;i="5.96,180,1665471600"; d="scan'208";a="729825533" Received: from tomnavar-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.209.176.15]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Nov 2022 16:28:05 -0800 From: Kai Huang To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: linux-mm@kvack.org, seanjc@google.com, pbonzini@redhat.com, dave.hansen@intel.com, dan.j.williams@intel.com, rafael.j.wysocki@intel.com, kirill.shutemov@linux.intel.com, ying.huang@intel.com, reinette.chatre@intel.com, len.brown@intel.com, tony.luck@intel.com, peterz@infradead.org, ak@linux.intel.com, isaku.yamahata@intel.com, chao.gao@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, bagasdotme@gmail.com, sagis@google.com, imammedo@redhat.com, kai.huang@intel.com Subject: [PATCH v7 17/20] x86/virt/tdx: Configure global KeyID on all packages Date: Mon, 21 Nov 2022 13:26:39 +1300 Message-Id: <8d8285cc5efa6302cf42a3fe2c9153d1a9dbcdac.1668988357.git.kai.huang@intel.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org After the array of TDMRs and the global KeyID are configured to the TDX module, use TDH.SYS.KEY.CONFIG to configure the key of the global KeyID on all packages. TDH.SYS.KEY.CONFIG must be done on one (any) cpu for each package. And it cannot run concurrently on different CPUs. Implement a helper to run SEAMCALL on one cpu for each package one by one, and use it to configure the global KeyID on all packages. Intel hardware doesn't guarantee cache coherency across different KeyIDs. The kernel needs to flush PAMT's dirty cachelines (associated with KeyID 0) before the TDX module uses the global KeyID to access the PAMT. Following the TDX module specification, flush cache before configuring the global KeyID on all packages. Given the PAMT size can be large (~1/256th of system RAM), just use WBINVD on all CPUs to flush. Note if any TDH.SYS.KEY.CONFIG fails, the TDX module may already have used the global KeyID to write any PAMT. Therefore, need to use WBINVD to flush cache before freeing the PAMTs back to the kernel. Note using MOVDIR64B (which changes the page's associated KeyID from the old TDX private KeyID back to KeyID 0, which is used by the kernel) to clear PMATs isn't needed, as the KeyID 0 doesn't support integrity check. Reviewed-by: Isaku Yamahata Signed-off-by: Kai Huang --- v6 -> v7: - Improved changelong and comment to explain why MOVDIR64B isn't used when returning PAMTs back to the kernel. --- arch/x86/virt/vmx/tdx/tdx.c | 89 ++++++++++++++++++++++++++++++++++++- arch/x86/virt/vmx/tdx/tdx.h | 1 + 2 files changed, 88 insertions(+), 2 deletions(-) diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c index 3a032930e58a..99d1be5941a7 100644 --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -224,6 +224,46 @@ static void seamcall_on_each_cpu(struct seamcall_ctx *sc) on_each_cpu(seamcall_smp_call_function, sc, true); } +/* + * Call one SEAMCALL on one (any) cpu for each physical package in + * serialized way. Return immediately in case of any error if + * SEAMCALL fails on any cpu. + * + * Note for serialized calls 'struct seamcall_ctx::err' doesn't have + * to be atomic, but for simplicity just reuse it instead of adding + * a new one. + */ +static int seamcall_on_each_package_serialized(struct seamcall_ctx *sc) +{ + cpumask_var_t packages; + int cpu, ret = 0; + + if (!zalloc_cpumask_var(&packages, GFP_KERNEL)) + return -ENOMEM; + + for_each_online_cpu(cpu) { + if (cpumask_test_and_set_cpu(topology_physical_package_id(cpu), + packages)) + continue; + + ret = smp_call_function_single(cpu, seamcall_smp_call_function, + sc, true); + if (ret) + break; + + /* + * Doesn't have to use atomic_read(), but it doesn't + * hurt either. + */ + ret = atomic_read(&sc->err); + if (ret) + break; + } + + free_cpumask_var(packages); + return ret; +} + static int tdx_module_init_cpus(void) { struct seamcall_ctx sc = { .fn = TDH_SYS_LP_INIT }; @@ -1010,6 +1050,22 @@ static int config_tdx_module(struct tdmr_info *tdmr_array, int tdmr_num, return ret; } +static int config_global_keyid(void) +{ + struct seamcall_ctx sc = { .fn = TDH_SYS_KEY_CONFIG }; + + /* + * Configure the key of the global KeyID on all packages by + * calling TDH.SYS.KEY.CONFIG on all packages in a serialized + * way as it cannot run concurrently on different CPUs. + * + * TDH.SYS.KEY.CONFIG may fail with entropy error (which is + * a recoverable error). Assume this is exceedingly rare and + * just return error if encountered instead of retrying. + */ + return seamcall_on_each_package_serialized(&sc); +} + /* * Detect and initialize the TDX module. * @@ -1098,15 +1154,44 @@ static int init_tdx_module(void) if (ret) goto out_free_pamts; + /* + * Hardware doesn't guarantee cache coherency across different + * KeyIDs. The kernel needs to flush PAMT's dirty cachelines + * (associated with KeyID 0) before the TDX module can use the + * global KeyID to access the PAMT. Given PAMTs are potentially + * large (~1/256th of system RAM), just use WBINVD on all cpus + * to flush the cache. + * + * Follow the TDX spec to flush cache before configuring the + * global KeyID on all packages. + */ + wbinvd_on_all_cpus(); + + /* Config the key of global KeyID on all packages */ + ret = config_global_keyid(); + if (ret) + goto out_free_pamts; + /* * Return -EINVAL until all steps of TDX module initialization * process are done. */ ret = -EINVAL; out_free_pamts: - if (ret) + if (ret) { + /* + * Part of PAMT may already have been initialized by + * TDX module. Flush cache before returning PAMT back + * to the kernel. + * + * Note there's no need to do MOVDIR64B (which changes + * the page's associated KeyID from the old TDX private + * KeyID back to KeyID 0, which is used by the kernel), + * as KeyID 0 doesn't support integrity check. + */ + wbinvd_on_all_cpus(); tdmrs_free_pamt_all(tdmr_array, tdmr_num); - else + } else pr_info("%lu pages allocated for PAMT.\n", tdmrs_count_pamt_pages(tdmr_array, tdmr_num)); out_free_tdmrs: diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h index c26bab2555ca..768d097412ab 100644 --- a/arch/x86/virt/vmx/tdx/tdx.h +++ b/arch/x86/virt/vmx/tdx/tdx.h @@ -15,6 +15,7 @@ /* * TDX module SEAMCALL leaf functions */ +#define TDH_SYS_KEY_CONFIG 31 #define TDH_SYS_INFO 32 #define TDH_SYS_INIT 33 #define TDH_SYS_LP_INIT 35