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 1FF63C433FE for ; Wed, 2 Mar 2022 14:29:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242983AbiCBOaR (ORCPT ); Wed, 2 Mar 2022 09:30:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243018AbiCBO3X (ORCPT ); Wed, 2 Mar 2022 09:29:23 -0500 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2EF6D50E19 for ; Wed, 2 Mar 2022 06:28:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646231298; x=1677767298; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=la+c8iM46i+BcjimR1ZxMdTr/2Sfz8iKXvQOOPZwCk8=; b=I1gMbU1+rJmAEIPfWWDxxUxowmhfa3heiapkxTb1kdYQ6OZK8E3zA3Qb ++Fr9mLlFh+mo8jbu1FANEOaFSWLA03Ag/9Gu6WsNbm+oL/tRq7lIXbcc bcA6Lbs0ZJGy4ykKNArewKIHzfhAgN4D9fqWF6fuJBd9PXhwy/sG/xi8a 46CHMgu96In3j7AwTviNMeGr5rlzuIM08Fqd86p9De5NKrGLUAvxBEVDV 0DWFAdxwObS8iPHBceoP+itggKdvWAToroWRgWRgKKI1w2wUEPEaS1/kp AFi85ZJMQL+vfA0t5SUTPsaj/j6dc2/bDVwnCNJZSSBRJomCzesAWGWmi g==; X-IronPort-AV: E=McAfee;i="6200,9189,10274"; a="240824396" X-IronPort-AV: E=Sophos;i="5.90,149,1643702400"; d="scan'208";a="240824396" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Mar 2022 06:28:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,149,1643702400"; d="scan'208";a="709524830" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga005.jf.intel.com with ESMTP; 02 Mar 2022 06:28:10 -0800 Received: by black.fi.intel.com (Postfix, from userid 1000) id 404FE647; Wed, 2 Mar 2022 16:28:13 +0200 (EET) From: "Kirill A. Shutemov" To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@intel.com, luto@kernel.org, peterz@infradead.org Cc: sathyanarayanan.kuppuswamy@linux.intel.com, aarcange@redhat.com, ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com, hpa@zytor.com, jgross@suse.com, jmattson@google.com, joro@8bytes.org, jpoimboe@redhat.com, knsathya@kernel.org, pbonzini@redhat.com, sdeep@vmware.com, seanjc@google.com, tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, thomas.lendacky@amd.com, brijesh.singh@amd.com, x86@kernel.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv5 29/30] ACPICA: Avoid cache flush inside virtual machines Date: Wed, 2 Mar 2022 17:28:05 +0300 Message-Id: <20220302142806.51844-30-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220302142806.51844-1-kirill.shutemov@linux.intel.com> References: <20220302142806.51844-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org WBINVD is not supported in TDX guest and triggers #VE. There's no robust way to emulate it. The kernel has to avoid it. ACPI_FLUSH_CPU_CACHE() flushes caches usign WBINVD on entering sleep states. It is required to prevent data loss. While running inside virtual machine, the kernel can bypass cache flushing. Changing sleep state in a virtual machine doesn't affect the host system sleep state and cannot lead to data loss. Signed-off-by: Kirill A. Shutemov --- arch/x86/include/asm/acenv.h | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/acenv.h b/arch/x86/include/asm/acenv.h index 9aff97f0de7f..d937c55e717e 100644 --- a/arch/x86/include/asm/acenv.h +++ b/arch/x86/include/asm/acenv.h @@ -13,7 +13,19 @@ /* Asm macros */ -#define ACPI_FLUSH_CPU_CACHE() wbinvd() +/* + * ACPI_FLUSH_CPU_CACHE() flushes caches on entering sleep states. + * It is required to prevent data loss. + * + * While running inside virtual machine, the kernel can bypass cache flushing. + * Changing sleep state in a virtual machine doesn't affect the host system + * sleep state and cannot lead to data loss. + */ +#define ACPI_FLUSH_CPU_CACHE() \ +do { \ + if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR)) \ + wbinvd(); \ +} while (0) int __acpi_acquire_global_lock(unsigned int *lock); int __acpi_release_global_lock(unsigned int *lock); -- 2.34.1