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 CA043EE4993 for ; Mon, 21 Aug 2023 16:16:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235016AbjHUQQa (ORCPT ); Mon, 21 Aug 2023 12:16:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233397AbjHUQQa (ORCPT ); Mon, 21 Aug 2023 12:16:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE67BA8 for ; Mon, 21 Aug 2023 09:16:28 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8B9C8613EA for ; Mon, 21 Aug 2023 16:16:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9AFBEC433C7; Mon, 21 Aug 2023 16:16:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1692634588; bh=GAhB9ATDBTLixCS7r9F7lYtkWg2M8bOfVJgbmkaGTiQ=; h=Subject:To:Cc:From:Date:From; b=b98yQdTFMc+z1aUROHKxCEOnoMdDN6MQPJmylAj6PRurcgWnWMpWPe/55Wn/fWzLl BZYtSNsllAxeFX3YKJO4ytm9lWo/Nk987rtlF4H8vAXENaJ33vy05kWeppcpu5qr6K gosE+UtUHclX0I+TD+quHVDEJi29+uYNTTkJQBuQ= Subject: FAILED: patch "[PATCH] x86/cpu/kvm: Provide UNTRAIN_RET_VM" failed to apply to 6.1-stable tree To: peterz@infradead.org, bp@alien8.de Cc: From: Date: Mon, 21 Aug 2023 18:16:25 +0200 Message-ID: <2023082125-untainted-putdown-eba5@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 864bcaa38ee44ec6c0e43f79c2d2997b977e26b2 # git commit -s git send-email --to '' --in-reply-to '2023082125-untainted-putdown-eba5@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 864bcaa38ee4 ("x86/cpu/kvm: Provide UNTRAIN_RET_VM") d893832d0e1e ("x86/srso: Add IBPB on VMEXIT") 233d6f68b98d ("x86/srso: Add IBPB") fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") 941d77c77339 ("Merge tag 'x86_cpu_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 864bcaa38ee44ec6c0e43f79c2d2997b977e26b2 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 14 Aug 2023 13:44:35 +0200 Subject: [PATCH] x86/cpu/kvm: Provide UNTRAIN_RET_VM Similar to how it doesn't make sense to have UNTRAIN_RET have two untrain calls, it also doesn't make sense for VMEXIT to have an extra IBPB call. This cures VMEXIT doing potentially unret+IBPB or double IBPB. Also, the (SEV) VMEXIT case seems to have been overlooked. Redefine the meaning of the synthetic IBPB flags to: - ENTRY_IBPB -- issue IBPB on entry (was: entry + VMEXIT) - IBPB_ON_VMEXIT -- issue IBPB on VMEXIT And have 'retbleed=ibpb' set *BOTH* feature flags to ensure it retains the previous behaviour and issues IBPB on entry+VMEXIT. The new 'srso=ibpb_vmexit' option only sets IBPB_ON_VMEXIT. Create UNTRAIN_RET_VM specifically for the VMEXIT case, and have that check IBPB_ON_VMEXIT. All this avoids having the VMEXIT case having to check both ENTRY_IBPB and IBPB_ON_VMEXIT and simplifies the alternatives. Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230814121149.109557833@infradead.org diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 5285c8e93dff..c55cc243592e 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -299,6 +299,17 @@ #endif .endm +.macro UNTRAIN_RET_VM +#if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \ + defined(CONFIG_CALL_DEPTH_TRACKING) || defined(CONFIG_CPU_SRSO) + VALIDATE_UNRET_END + ALTERNATIVE_3 "", \ + CALL_UNTRAIN_RET, X86_FEATURE_UNRET, \ + "call entry_ibpb", X86_FEATURE_IBPB_ON_VMEXIT, \ + __stringify(RESET_CALL_DEPTH), X86_FEATURE_CALL_DEPTH +#endif +.endm + .macro UNTRAIN_RET_FROM_CALL #if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \ defined(CONFIG_CALL_DEPTH_TRACKING) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 6f3e19527286..9026e3fe9f6c 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1054,6 +1054,7 @@ static void __init retbleed_select_mitigation(void) case RETBLEED_MITIGATION_IBPB: setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB); + setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT); mitigate_smt = true; break; diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S index 265452fc9ebe..ef2ebabb059c 100644 --- a/arch/x86/kvm/svm/vmenter.S +++ b/arch/x86/kvm/svm/vmenter.S @@ -222,10 +222,7 @@ SYM_FUNC_START(__svm_vcpu_run) * because interrupt handlers won't sanitize 'ret' if the return is * from the kernel. */ - UNTRAIN_RET - - /* SRSO */ - ALTERNATIVE "", "call entry_ibpb", X86_FEATURE_IBPB_ON_VMEXIT + UNTRAIN_RET_VM /* * Clear all general purpose registers except RSP and RAX to prevent @@ -362,7 +359,7 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run) * because interrupt handlers won't sanitize RET if the return is * from the kernel. */ - UNTRAIN_RET + UNTRAIN_RET_VM /* "Pop" @spec_ctrl_intercepted. */ pop %_ASM_BX