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 21028C4167E for ; Tue, 12 Apr 2022 12:47:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354160AbiDLMtw (ORCPT ); Tue, 12 Apr 2022 08:49:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355240AbiDLMsI (ORCPT ); Tue, 12 Apr 2022 08:48:08 -0400 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF98D10FCC for ; Tue, 12 Apr 2022 05:15:28 -0700 (PDT) Received: by mail-pj1-x1035.google.com with SMTP id nt14-20020a17090b248e00b001ca601046a4so2719698pjb.0 for ; Tue, 12 Apr 2022 05:15:28 -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=1flPZn7KfxFftAsobgisj3+41XCbW7e4EGW5Tqzb8+g=; b=Nf0HpfxvT7Ry4yE7lVio3FcL8ye5fqe2hbFqsnPm43aqNED8RDsVAVtWp6jBk8jYef ymkf3/C7FGfZJKsfhdqDL3D002DtQMYuybDOZAAp5kecqmxeKzmRZfQgtPB7GTuSmr+v 0gtXEBSjDtRiZwF6Eo5qv7dB+QUMSdzkmE9421aDGRd96pKvTk8PWV2fHqL2V9uyL/Nt KJSoWYzeuy3J0Lauv+5GIwPftXh683H+zV0qRjdDZvfIkd54YGRey/kUhaSG0xcyJJW/ W5eyIzTXisvU91p9mmxJn+UycK0ZY+KnuPM532WfLqn3Q3zHefC1aQQMC1xZANLg3R5o OkLw== 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=1flPZn7KfxFftAsobgisj3+41XCbW7e4EGW5Tqzb8+g=; b=Kml10JMZvS8mXGl4w7OpWZfNWj8UKCEGstYXJ4RWx1YQnchdwflQfJxftDiVa9klMV 10shoDelatLcOgVhpbfx6bB8JvgYYjknzLCQfbFjwKzNxmRY+ffOp5AH7dp+FxnLi0fh XqWpRrhzJUv+HwZMeelMsuEEzV8Btk8cWe3Z9i5IvYh4uJ6x8dsq3F2fprU8yL/HE9Jv SPNl6pMddmWJxlNgvZ1fOzbIegULcJIYUWSSmsqkEwvoTa//NvD/hdGeX8Wq5p24eZGJ sTq2k1wideWEhs+/6nuk0gtpxJoL/OWbr301CZJrfwl6BaadA2jZrP0Dh2tNjPBQf3S6 YqUg== X-Gm-Message-State: AOAM5313RwEZnW4hB3nfNdLzxvF9DoWolWmjPfhJCMcpt/RqIsX/rl95 5PY2z4kXDyjShWZlzTK3NF2j+wDY97s= X-Google-Smtp-Source: ABdhPJwUp+KmSkve9HAzkexmkq8wQ8btJVq2enI/a9m27a5Bb6LymOdTUfdCpHULLpOqWI9zopMBaA== X-Received: by 2002:a17:902:c2d8:b0:154:b384:917b with SMTP id c24-20020a170902c2d800b00154b384917bmr38234316pla.58.1649765728232; Tue, 12 Apr 2022 05:15:28 -0700 (PDT) Received: from localhost ([47.251.4.198]) by smtp.gmail.com with ESMTPSA id c18-20020a056a000ad200b004f0f9696578sm42206082pfl.141.2022.04.12.05.15.27 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Apr 2022 05:15:27 -0700 (PDT) From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: Borislav Petkov , Peter Zijlstra , Josh Poimboeuf , Andy Lutomirski , Thomas Gleixner , x86@kernel.org, Lai Jiangshan , Ingo Molnar , Dave Hansen , "H. Peter Anvin" Subject: [PATCH V5 5/7] x86/entry: Don't call error_entry() for XENPV Date: Tue, 12 Apr 2022 20:15:39 +0800 Message-Id: <20220412121541.4595-6-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20220412121541.4595-1-jiangshanlai@gmail.com> References: <20220412121541.4595-1-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. 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 7b6a0f15bb20..3aca7815fe79 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -328,8 +328,17 @@ SYM_CODE_END(ret_from_fork) PUSH_AND_CLEAR_REGS ENCODE_FRAME_POINTER - 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