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 0C476C433EF for ; Thu, 21 Apr 2022 14:11:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1389078AbiDUONt (ORCPT ); Thu, 21 Apr 2022 10:13:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50200 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1389020AbiDUONd (ORCPT ); Thu, 21 Apr 2022 10:13:33 -0400 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44BDF3B022 for ; Thu, 21 Apr 2022 07:10:44 -0700 (PDT) Received: by mail-pl1-x631.google.com with SMTP id q3so4991045plg.3 for ; Thu, 21 Apr 2022 07:10:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=VgGgMxYprzA3l/xL3EqCp11c0RZBUqA2IVp2y5zwqwA=; b=M36LrAYWtb8/DoIhQ7z4mrZyLrYcU/P5mDTC8OcvJeJwkp5xp8E/y7f+cIJhpcGd44 BvYLzOew7P4Py83ksLyx9FX0mCGqSP21YfUc2Xfl6rmzBp1aUhIVu/j78Dc/jB/GZZZ2 TXv4Ga/iBpaNrPhhnBx2hzVkSlaplNMGKTGoiMmPDASV/GIYouSrciYUG+Ib0o7vPX/Z L0jhhEgeZg5A26zJpfarDt3zFdgCvdoa+xpBQYrp1tC5Yx74frA+Sl9zD6BSujs74orn o9b3aiZEzdyXuKfgb2lHXit0Ts6B8S1iE0vbUiVMmxucEUkeNphg4hfpPtuQqD+LBXz1 hdDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=VgGgMxYprzA3l/xL3EqCp11c0RZBUqA2IVp2y5zwqwA=; b=F1eft448SYSPSc1fuMWRBnRary0434hV/QQ0AVRFwmfrHSQq/2/05KC5+B2Tf20/Ge Lnsygs6BYc4+FWiyaghLBxKNLWJHyKDgf4kH+JlZ3yRhsxatN2kiAQMKz+bQkU1GBVHv OEJkCuZvNbJBKUCchGarVjYFdmBh1HRxfG2HW0Az8z9pNwoku3MqisNaJ2HMRLIth3Ks gEfP/iacFAUsHO/TPL7HgJ1FeRjhVt8r2AJQkrbAJGqhb0nVyczjheo83IHgXWgL+t2O oYJ6OSUPxK7jUmFkhJD//g1HF3VvaHpBhnZ0pNKbMy9hBW8tOIs8YWKwOXhGhx6JkD/Q clsQ== X-Gm-Message-State: AOAM530013Mh/fvixeUPnEXUJISv8yAvlY7JCFao4gc6xBO4lJ26VSL3 nVtkKpCTfkBSmEHYu0BbXd8iODb9+CQ= X-Google-Smtp-Source: ABdhPJxX/H8qICvWj3ZVLuik1LZmVooJXj2X2VrvAd6Bo8EThbQNUg/GImEzOpiauwj5/xCyYdKGXQ== X-Received: by 2002:a17:90b:3c47:b0:1cb:8121:dcc8 with SMTP id pm7-20020a17090b3c4700b001cb8121dcc8mr10800735pjb.35.1650550243502; Thu, 21 Apr 2022 07:10:43 -0700 (PDT) Received: from localhost ([47.251.4.198]) by smtp.gmail.com with ESMTPSA id m1-20020a17090ade0100b001cb3feaddfcsm2672000pjv.2.2022.04.21.07.10.42 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Apr 2022 07:10:43 -0700 (PDT) From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: Borislav Petkov , Peter Zijlstra , Josh Poimboeuf , Andy Lutomirski , Thomas Gleixner , Juergen Gross , x86@kernel.org, Lai Jiangshan , Ingo Molnar , Dave Hansen , "H. Peter Anvin" Subject: [PATCH V6 5/8] x86/entry: Don't call error_entry() for XENPV Date: Thu, 21 Apr 2022 22:10:52 +0800 Message-Id: <20220421141055.316239-6-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20220421141055.316239-1-jiangshanlai@gmail.com> References: <20220421141055.316239-1-jiangshanlai@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lai Jiangshan When in XENPV, it is already in the task stack, and it can't fault for native_iret() nor native_load_gs_index() since XENPV uses its own pvops for IRET and load_gs_index(). And it doesn't need to switch the CR3. So there is no reason to call error_entry() in XENPV. Cc: Juergen Gross Signed-off-by: Lai Jiangshan --- arch/x86/entry/entry_64.S | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index ab6ab6d3dab5..062aa9d95961 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -336,8 +336,17 @@ SYM_CODE_END(push_and_clear_regs) call push_and_clear_regs UNWIND_HINT_REGS - call error_entry - movq %rax, %rsp /* switch to the task stack if from userspace */ + /* + * Call error_entry() and switch to the task stack if from userspace. + * + * When in XENPV, it is already in the task stack, and it can't fault + * for native_iret() nor native_load_gs_index() since XENPV uses its + * own pvops for IRET and load_gs_index(). And it doesn't need to + * switch the CR3. So it can skip invoking error_entry(). + */ + ALTERNATIVE "call error_entry; movq %rax, %rsp", \ + "", X86_FEATURE_XENPV + ENCODE_FRAME_POINTER UNWIND_HINT_REGS -- 2.19.1.6.gb485710b