From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6C11037CD4F; Tue, 24 Mar 2026 18:17:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774376265; cv=none; b=gh0Mdq/Kbr3cLZ8frmVUogJwcF41HJdhaZfw0LWu0OrGMcNHDNuHEOhyNOhoefbFvzMgYuLA2TwAS5kRPzsuiRtIpb43CHolRuCYnoDUfFU6LScsdVFKClQ3SBMziSVPW700qlAVc5FBsB1+8f2anC6jGH6K5myt88eIn2S+vZU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774376265; c=relaxed/simple; bh=iKbYaTDuUMcCWsnSDj/iaOVKUwO2Qpaue4niM52YYmE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Lfua7nYaUG957vF20lsUN9mJfZlGRJFq15nzX5K5cHMOId6IJ7aqO1acO8fSn5n6YbRWqM4Vrvu0WmzRTAzxD0jV9Yblyeyp23av1kJsDpw98fwWudjhfCa4ASRzbf1xnWB15ZNikLLVFtkOGC/tSiIopG4A0KuP9NcSGYrJJyk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=TMy+eA9K; arc=none smtp.client-ip=198.175.65.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="TMy+eA9K" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1774376263; x=1805912263; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=iKbYaTDuUMcCWsnSDj/iaOVKUwO2Qpaue4niM52YYmE=; b=TMy+eA9KxcPR4IYemwOD3FadN6ClYWie+S8/uh2u0+aYEmkW4c/Bi3Gt VTcnCqJ7Quwi9mNdqlisOLia4aQSNsWGjxqp+kpyMwFleNVhZIZqTm/bD /RrCWgzt2MtqXmyW1jMq5JsVm9ml4BzZ+Vd65MuuQ3wGSPlue4XDWFnMZ vI0MTTBY00tCSYXbQ8lCTuOCS1iEgNPojbDODbZe0O2Vz2ThF+dSOY1Qu DRjG8ww+9ezqbUIFVW8IBvfzPJCzSTbcGDD5nGsucHghK806AmG/YMtzD ysa8LRSLElhh5WBlsry5+5djIKagoS73YV+PjvCQNgUYAg3inlYOFdq1x A==; X-CSE-ConnectionGUID: 31iMJ4IIQsysbWFra6uHcA== X-CSE-MsgGUID: VroQMhoKTGSCCWgZuVLkUg== X-IronPort-AV: E=McAfee;i="6800,10657,11739"; a="86479970" X-IronPort-AV: E=Sophos;i="6.23,138,1770624000"; d="scan'208";a="86479970" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Mar 2026 11:17:42 -0700 X-CSE-ConnectionGUID: zgdaje3hSoeNZiG9eprngQ== X-CSE-MsgGUID: Gy+6QpTmQrSaRUz73o2pqw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,138,1770624000"; d="scan'208";a="217858388" Received: from guptapa-desk.jf.intel.com (HELO desk) ([10.165.239.46]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Mar 2026 11:17:42 -0700 Date: Tue, 24 Mar 2026 11:17:41 -0700 From: Pawan Gupta To: x86@kernel.org, Jon Kohler , Nikolay Borisov , "H. Peter Anvin" , Josh Poimboeuf , David Kaplan , Sean Christopherson , Borislav Petkov , Dave Hansen , Peter Zijlstra , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , KP Singh , Jiri Olsa , "David S. Miller" , David Laight , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , David Ahern , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , Stanislav Fomichev , Hao Luo , Paolo Bonzini , Jonathan Corbet Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Asit Mallick , Tao Zhang , bpf@vger.kernel.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH v8 05/10] x86/vmscape: Move mitigation selection to a switch() Message-ID: <20260324-vmscape-bhb-v8-5-68bb524b3ab9@linux.intel.com> X-Mailer: b4 0.15-dev References: <20260324-vmscape-bhb-v8-0-68bb524b3ab9@linux.intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260324-vmscape-bhb-v8-0-68bb524b3ab9@linux.intel.com> This ensures that all mitigation modes are explicitly handled, while keeping the mitigation selection for each mode together. This also prepares for adding BHB-clearing mitigation mode for VMSCAPE. Reviewed-by: Nikolay Borisov Signed-off-by: Pawan Gupta --- arch/x86/kernel/cpu/bugs.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 47c020b80371..68e2df3e3bf5 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -3084,17 +3084,33 @@ early_param("vmscape", vmscape_parse_cmdline); static void __init vmscape_select_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_VMSCAPE) || - !boot_cpu_has(X86_FEATURE_IBPB)) { + if (!boot_cpu_has_bug(X86_BUG_VMSCAPE)) { vmscape_mitigation = VMSCAPE_MITIGATION_NONE; return; } - if (vmscape_mitigation == VMSCAPE_MITIGATION_AUTO) { - if (should_mitigate_vuln(X86_BUG_VMSCAPE)) + if ((vmscape_mitigation == VMSCAPE_MITIGATION_AUTO) && + !should_mitigate_vuln(X86_BUG_VMSCAPE)) + vmscape_mitigation = VMSCAPE_MITIGATION_NONE; + + switch (vmscape_mitigation) { + case VMSCAPE_MITIGATION_NONE: + break; + + case VMSCAPE_MITIGATION_IBPB_EXIT_TO_USER: + if (!boot_cpu_has(X86_FEATURE_IBPB)) + vmscape_mitigation = VMSCAPE_MITIGATION_NONE; + break; + + case VMSCAPE_MITIGATION_AUTO: + if (boot_cpu_has(X86_FEATURE_IBPB)) vmscape_mitigation = VMSCAPE_MITIGATION_IBPB_EXIT_TO_USER; else vmscape_mitigation = VMSCAPE_MITIGATION_NONE; + break; + + default: + break; } } -- 2.34.1