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 8EF9EC433F5 for ; Fri, 18 Mar 2022 14:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237304AbiCRObf (ORCPT ); Fri, 18 Mar 2022 10:31:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237284AbiCRObb (ORCPT ); Fri, 18 Mar 2022 10:31:31 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D74F55DE55 for ; Fri, 18 Mar 2022 07:30:11 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id bx5so7537158pjb.3 for ; Fri, 18 Mar 2022 07:30:11 -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=p16mVRwfAs4lOC/jhpdduor9Cpu9c9v3C71RdCE1eKU=; b=k2UBtOMTP5XnazjZlWUlQAkBTrclhFjgpu6Vn/6fC4rZIygIgiqhuzR2tVVQH9IxHY 5/MeBbTVOEBy8HQw3QWQ9Hy8yjCJzPAO+Slf8ZYit9ppQutXpc0WiK7QcYqfUFzBUgaI 9ZMn8G6rPEj3ilRFdhDI7uCT/rAX7i3K1+XLcQ9capSr7Kwo1/43480eAaroz/hUVbci Tn3WS23QreUG2SZO7DGzP5WEkkxvlv9GaiWMi3pNEi91FNgyALnje0STgu/sv9v8H+an iC3Gcn6tXUvgTeTORHegDDbEZwi8F+gEsDR3GJ+aBlcLyMWRLk10JyyVhy08B09NZkF1 BQ4w== 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=p16mVRwfAs4lOC/jhpdduor9Cpu9c9v3C71RdCE1eKU=; b=jQR/0dr7dz0gUINpXFHJoJUfWqZ7+ENULIjUBbOstuHFpf+3xP0zO3E9L3nXClLfj2 6GFWcd9QUeM7EDvyewBGQjq0FmjJeO8QlfSccEPxsoOw5gxbayegzrRhis4HzJiS6d9X c0DfkmQlXNDBMOfpWL86xRYBv/KWNAkauOMsq+oUhULo+7sV2Pb4EL7NcQMDngeIwAVq n7nCFMaZEPVaYgmE/3X8T4kj71zoleZXOwzi+bvc5TAnQRIPbnkmYReAEFPmQejsdnom T/nTNo23nAJf5NbnYR8g+Ltt4IS0WdOwSELdRx6lnPic/ZRx4N/US9XKzmbSO+sEXwTV +W8A== X-Gm-Message-State: AOAM531HyukQGeDXhVP/UYVHjpi8oZeAvp2kQCR0FGuBRekWNRqL0pf6 xYDqVvhQSB/SWKVSmSI3BCQkBTq5MQw= X-Google-Smtp-Source: ABdhPJyrKXLLP4SUQc0RG8A6ybc/o7QcU+F9ALNyMcXTy9LLeuHTseNT4hg5cloDQXs885RIuUgoxQ== X-Received: by 2002:a17:902:d2cc:b0:152:fda8:f3ff with SMTP id n12-20020a170902d2cc00b00152fda8f3ffmr10465772plc.92.1647613810403; Fri, 18 Mar 2022 07:30:10 -0700 (PDT) Received: from localhost ([47.251.4.198]) by smtp.gmail.com with ESMTPSA id z5-20020a056a00240500b004e15d39f15fsm9982929pfh.83.2022.03.18.07.30.09 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 Mar 2022 07:30:10 -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 V4 5/7] x86/entry: Don't call error_entry for XENPV Date: Fri, 18 Mar 2022 22:30:14 +0800 Message-Id: <20220318143016.124387-6-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20220318143016.124387-1-jiangshanlai@gmail.com> References: <20220318143016.124387-1-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 8121b9f3fceb..e9fe9f00d17c 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 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