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 D422AC433F5 for ; Tue, 15 Mar 2022 07:40:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345565AbiCOHlQ (ORCPT ); Tue, 15 Mar 2022 03:41:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345595AbiCOHlE (ORCPT ); Tue, 15 Mar 2022 03:41:04 -0400 Received: from mail-pf1-x432.google.com (mail-pf1-x432.google.com [IPv6:2607:f8b0:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 899874B436 for ; Tue, 15 Mar 2022 00:39:53 -0700 (PDT) Received: by mail-pf1-x432.google.com with SMTP id s8so18262617pfk.12 for ; Tue, 15 Mar 2022 00:39:53 -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=F47NijhW68SKqc1BYAUjtn551pZ33aNYyOQgE9AVSDc=; b=fqKS6i+KlVpg6+nqo4tBqUZmUTLYnarlbnbmEjnoWzXn9GwJstTgZCknaGOx0PdjEf jAOWt58SOCSf/dlNN+cNPCdi3/TUlf1dG5l3j4Tq0Ja67LcW63n3+LvdwiOrbaRu5Go6 RlqrmRY1QmqEwJNxk3yORt44s5yulSzTXPS5O7MZOLkG5lh3p+k7gdcy7e976Xw9GbZ1 JfaYFiT3S1Qw3j3CJeORhWvy7UMzBlDir1ONT7MshL87BlqPSEE7qMVq+mBohBs65avh yWokbe4qjXxzhv8FDIER5vrn/3ge7Lt/bqkfFsILk3qRwXcrl550gp3dgrvVZ+VYxWwu ZaAA== 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=F47NijhW68SKqc1BYAUjtn551pZ33aNYyOQgE9AVSDc=; b=DiC9N8Qxr3T5kT5SP8S8K++mz6FK0D1ZGTysGusBIHPfnDrpoeyMiE7U+BGP+6ZkGG 8IA0Wt4HJyA6pwlxEKnkwYgFrJb/Y6VjsMN+fFZ0gKrYeiiMN6h19ns2d/ddoODrQ7MA O3e7WGVp66RFaxqUuyXzn+RpJPHujzaq3bQyODtgVfKBM2YvKN+QxZCeOmDTVi+tIVgy FpiO85JYTZ2tRZmL2D6cvnBU2f0p/w5Q+rljRW7SEPf8EoPMPLL78GXwlPJBpQdjtV9U XzTiU0a0N+5zdHUb16UH4Wi7/Hnv6Vs6H61zoq2VabyUpaAtxZUTbDhThQUEbaYDZLpl jJoQ== X-Gm-Message-State: AOAM532xWDek2cBDbkygJhmqXpByWIrBUbVILU32WHrl0wfNIu1BOKq3 5nvrDYJ1bOb9MiP2CBLSt9Xh7roq/bE= X-Google-Smtp-Source: ABdhPJwaLUUAyeBa1DbtwyyQJmWkAUxohn03gbxPjCJO9/soJ6AfgeEnYpzW2l0yw0aBE5ap2madoQ== X-Received: by 2002:a65:6794:0:b0:36c:460e:858d with SMTP id e20-20020a656794000000b0036c460e858dmr22949141pgr.418.1647329992887; Tue, 15 Mar 2022 00:39:52 -0700 (PDT) Received: from localhost ([47.251.4.198]) by smtp.gmail.com with ESMTPSA id k14-20020a056a00134e00b004f83f05608esm4044796pfu.31.2022.03.15.00.39.51 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 15 Mar 2022 00:39:52 -0700 (PDT) From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Borislav Petkov , Peter Zijlstra , Lai Jiangshan , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Dave Hansen , "H. Peter Anvin" Subject: [PATCH V3 6/7] x86/entry: Don't call error_entry for XENPV Date: Tue, 15 Mar 2022 15:39:48 +0800 Message-Id: <20220315073949.7541-7-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20220315073949.7541-1-jiangshanlai@gmail.com> References: <20220315073949.7541-1-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 e4a07276fd1c..ec885c2107de 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