From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 AFA8D3C17; Fri, 31 Oct 2025 14:05:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761919558; cv=none; b=I9g7Srgr6/svYFKI+ktX4U9kEjbI/uZsb7/j9Nm1sexUrTkdjKmlGvmEtudfnyqRW4ZWBg/lQcFw/M0I5a7ZxjhP3p9Ep6dGx8sARKKLo5EP+pHcGd6NSR3usWnYwZB4dGqyQfqcIIeGUcevqqBMBIl4K8W2j2+cr6sMQthbufA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761919558; c=relaxed/simple; bh=I0Bt8/hOyrKTatjUlV+jQVod56rUEr/f5fwWxgV0InQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Sj8GCr1NhMG4aR4wa4vfjjoM/7YpyGMC2a9TXeQJ0sGDQ1Viy9/8Q44v6z3bHEUikOkiF1pi3L5IlH606dic0Q7XrIUES781lHcc0UBlzHC+ucLMuwQ9JgmkwleQYzVsOfMc5JGQEnvGDOlgb/dxsX+J/cXAgrJ4YCSSBUbYhew= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xQgYJ03r; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xQgYJ03r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 371B1C4CEE7; Fri, 31 Oct 2025 14:05:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1761919558; bh=I0Bt8/hOyrKTatjUlV+jQVod56rUEr/f5fwWxgV0InQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xQgYJ03r+wIK1aBjw4fOnVc6U8KoAN7dUT1ajYn5a49TNG0Sy85FsIhkxiXjd/g+T eiljYttH2HTC9BQ4nj0w3L+GNiN26N2+gPFjOSD/t35YfofgA/+YWktmcmBTwIRPsN DF41a62kiw6UyQPfPm3VAraYW8ZUeBlJLzVliTzA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Kaplan , "Borislav Petkov (AMD)" , Sasha Levin Subject: [PATCH 6.17 19/35] x86/bugs: Add attack vector controls for VMSCAPE Date: Fri, 31 Oct 2025 15:01:27 +0100 Message-ID: <20251031140044.023887631@linuxfoundation.org> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20251031140043.564670400@linuxfoundation.org> References: <20251031140043.564670400@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Kaplan [ Upstream commit 5799d5d8a6c877f03ad5b5a640977053be45059a ] Use attack vector controls to select whether VMSCAPE requires mitigation, similar to other bugs. Signed-off-by: David Kaplan Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Sasha Levin --- .../admin-guide/hw-vuln/attack_vector_controls.rst | 1 + arch/x86/kernel/cpu/bugs.c | 14 ++++++++++---- 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/Documentation/admin-guide/hw-vuln/attack_vector_controls.rst b/Documentation/admin-guide/hw-vuln/attack_vector_controls.rst index 5964901d66e31..d0bdbd81dcf9f 100644 --- a/Documentation/admin-guide/hw-vuln/attack_vector_controls.rst +++ b/Documentation/admin-guide/hw-vuln/attack_vector_controls.rst @@ -218,6 +218,7 @@ SRSO X X X X SSB X TAA X X X X * (Note 2) TSA X X X X +VMSCAPE X =============== ============== ============ ============= ============== ============ ======== Notes: diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 9750ce448e626..c6bb8e76eb984 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -434,6 +434,9 @@ static bool __init should_mitigate_vuln(unsigned int bug) case X86_BUG_SPEC_STORE_BYPASS: return cpu_attack_vector_mitigated(CPU_MITIGATE_USER_USER); + case X86_BUG_VMSCAPE: + return cpu_attack_vector_mitigated(CPU_MITIGATE_GUEST_HOST); + default: WARN(1, "Unknown bug %x\n", bug); return false; @@ -3308,15 +3311,18 @@ early_param("vmscape", vmscape_parse_cmdline); static void __init vmscape_select_mitigation(void) { - if (cpu_mitigations_off() || - !boot_cpu_has_bug(X86_BUG_VMSCAPE) || + if (!boot_cpu_has_bug(X86_BUG_VMSCAPE) || !boot_cpu_has(X86_FEATURE_IBPB)) { vmscape_mitigation = VMSCAPE_MITIGATION_NONE; return; } - if (vmscape_mitigation == VMSCAPE_MITIGATION_AUTO) - vmscape_mitigation = VMSCAPE_MITIGATION_IBPB_EXIT_TO_USER; + if (vmscape_mitigation == VMSCAPE_MITIGATION_AUTO) { + if (should_mitigate_vuln(X86_BUG_VMSCAPE)) + vmscape_mitigation = VMSCAPE_MITIGATION_IBPB_EXIT_TO_USER; + else + vmscape_mitigation = VMSCAPE_MITIGATION_NONE; + } } static void __init vmscape_update_mitigation(void) -- 2.51.0