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 C8EC4C4332F for ; Wed, 8 Dec 2021 11:09:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229503AbhLHLMk (ORCPT ); Wed, 8 Dec 2021 06:12:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232145AbhLHLMb (ORCPT ); Wed, 8 Dec 2021 06:12:31 -0500 Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A02B4C061A72 for ; Wed, 8 Dec 2021 03:08:59 -0800 (PST) Received: by mail-pf1-x42d.google.com with SMTP id r130so2189162pfc.1 for ; Wed, 08 Dec 2021 03:08:59 -0800 (PST) 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=GTzYOcv7GXMsuudeRCCVKvQE4p4RTznbhZKVu0xYKUU=; b=km30WDN3p/x6O1LN4IM4fy77QF1NVRUPK5sP06Gal6+QGtjqpUUYFI0ArnBEImqtBx AuUANxaE5TNvqfzwlIxrjFaBsxfD6p1eT/U6KemlwxP4SBJRnkOXwocKlRobPiXwphiK nnKNx8a17oUYe1aBF9xVYjEfT0JHyVlsyWpuNHWRttKft7eHMogyjA4hHEpDixYozui/ Yp9HWHVmMbUx0pUgEzC7X+43ukc3qPqWPrcwKNA92/m1IkWkKcYC2169qQXVTznVDh9C 8FdQ3N0QnfLfiyMM1qnRw3/LhI95W2mPf5Ae8J85boc7Vk+qIFVR2qqDY1HLZcu21xTg Tx+g== 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=GTzYOcv7GXMsuudeRCCVKvQE4p4RTznbhZKVu0xYKUU=; b=rk51IO8Z2pFsBJOZLXmcVFC8a57RB3cRfZa2SI6WsMsg2WmcPL+0JVaNmZ1zGc8NLp GdrI/oPD7D8OCgjfdrck/x4Tx/VYKmKBdO1twosKy7DfNK7xf8jhUm7ZvNSed6jEg11R uLrHCPvpAWGj6rHSGoYJRuUGfJXvTQxv73jgdjE93USAlG+x4mCFnvDMAMSw4Uo2qe+z 9eVFe0YGnI7nXD3h6tg6pkj/fkFbpQDjOal0IB/+ff5qsE1cAlMVlFUhWzLUNwsR7OlQ Wp0WuodVosiek0whQIUvik+6PBMWB6AyE2iBIqVGoUl2GX/U1VycFkLpw3FIQMCF4KmS qj9A== X-Gm-Message-State: AOAM533wl+Tb82663nCre/EVHuAxNpTYjjD+XHKg/0iKUeS+OuW+k1Dv zN0+GRS3ANTeEEbkf7VTYGYk+s5dd7o= X-Google-Smtp-Source: ABdhPJyG8RspzExM0YLJHIGBovB6b/ZNv9oPLLxl7bIY/uiUpBpyPdvWlt/3qAb05wwKy/zxp0w/Lw== X-Received: by 2002:a05:6a00:ad0:b0:4a3:1056:e2ae with SMTP id c16-20020a056a000ad000b004a31056e2aemr4931125pfl.2.1638961739024; Wed, 08 Dec 2021 03:08:59 -0800 (PST) Received: from localhost ([47.251.3.230]) by smtp.gmail.com with ESMTPSA id gc22sm5791712pjb.57.2021.12.08.03.08.57 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 08 Dec 2021 03:08:58 -0800 (PST) From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, xen-devel@lists.xenproject.org, Lai Jiangshan , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Subject: [PATCH 06/11] x86/entry: Don't call error_entry for XENPV Date: Wed, 8 Dec 2021 19:08:28 +0800 Message-Id: <20211208110833.65366-7-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20211208110833.65366-1-jiangshanlai@gmail.com> References: <20211208110833.65366-1-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 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 ee1d4adcdab0..383070aa9272 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -325,8 +325,17 @@ SYM_CODE_END(ret_from_fork) PUSH_AND_CLEAR_REGS ENCODE_FRAME_POINTER - call error_entry - movq %rax, %rsp /* switch stack settled by sync_regs() */ + /* + * Call error_entry and switch stack settled by sync_regs(). + * + * 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 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