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 5DAC8C433F5 for ; Tue, 3 May 2022 03:21:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230384AbiECDYq (ORCPT ); Mon, 2 May 2022 23:24:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230355AbiECDYg (ORCPT ); Mon, 2 May 2022 23:24:36 -0400 Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 689E03B283 for ; Mon, 2 May 2022 20:21:05 -0700 (PDT) Received: by mail-pl1-x62c.google.com with SMTP id s14so13970935plk.8 for ; Mon, 02 May 2022 20:21:05 -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=S+Zz45MWXks4nx4ynNsiBuY3M56T6z4EiXW0WpmvNvAkBcDnPi8B/Nxm2oX3Z21Nlh o9DHs790/56cgU/3G6nNFMfyqo94VMk0tay8JMcYI3+N971ZUh3amcaL689ltG6XmDuY IK2GaVJXyrqdi7LJ+/F3TB5iEgSQiq7w5IUtDss4ocWgJxoLIwITm2xPzG8440Bo0dDT yBXkbyKCNdx8kCSIqKduqeO3rZB/PqYVuTCEx5wvgUwqMP5HX6nW8rFauA1sRdEDHGQ7 oPQPH2ApTrqLUkj+keH1EdMrx4W7pEAFHOyQzYwcTHI8fptOHu6Ny+CLiOemC2rKRET6 KkDA== 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=BJnx5WT/kNBZ4FR7nLW7S7t3v/fsXQ/AMF9/nh7DfG5dNXBfe8yvSUbW4uGchtRBWZ p9UAvK/B7oseieUVEOvum3ZxPKu1mgclD2CZHB2jstnHpRuC8MmYe56/xoDJe6ZxJAL2 z3pwTZDeJtryZVL8WH6hBTlQwG8KiqHgdif86nMCHiWRmaZy0B8tEuJ8cSeOQciCEkuZ PiaOMr9Tg9P6F+6+29P1BVWsyVJ/h6CbonbVXVB5koYfaB4y69lb7SgFFl9tIXDImpFu T1Wjr1zZcaZsNNDSDsX6UQMt/obKhI7JEbVIvpx82geDqhZEVM81u6MTO7DHJy+u/Srz ofmA== X-Gm-Message-State: AOAM530wUoIWTo7CHeJRH0oFjtG3DU5iYYa9/0MLDwnwK6POkGsqmVnf 4YtnnrYO8FXE2VlRR+qrjOcNrEz4nGo= X-Google-Smtp-Source: ABdhPJzCceSsy+gBasYlsMUGbi/7N68x5v0EIJSpy2AZTAAtMRoJOfWLebTQyavueQvCLGEv1Mc4Xw== X-Received: by 2002:a17:90a:488c:b0:1c7:b62e:8e8c with SMTP id b12-20020a17090a488c00b001c7b62e8e8cmr2477589pjh.157.1651548064578; Mon, 02 May 2022 20:21:04 -0700 (PDT) Received: from localhost ([47.251.4.198]) by smtp.gmail.com with ESMTPSA id a17-20020a631a51000000b003c14af5060fsm11896873pgm.39.2022.05.02.20.21.03 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 May 2022 20:21:04 -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 V7 5/6] x86/entry: Don't call error_entry() for XENPV Date: Tue, 3 May 2022 11:21:06 +0800 Message-Id: <20220503032107.680190-6-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20220503032107.680190-1-jiangshanlai@gmail.com> References: <20220503032107.680190-1-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