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 X-Spam-Level: X-Spam-Status: No, score=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B75DC4361A for ; Fri, 4 Dec 2020 18:38:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD30322C9C for ; Fri, 4 Dec 2020 18:38:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730039AbgLDSi1 (ORCPT ); Fri, 4 Dec 2020 13:38:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:48484 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728475AbgLDSi1 (ORCPT ); Fri, 4 Dec 2020 13:38:27 -0500 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8267E22C9C; Fri, 4 Dec 2020 18:37:46 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1klFxg-00G3Uh-Om; Fri, 04 Dec 2020 18:37:44 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Cc: Will Deacon , James Morse , Julien Thierry , Suzuki K Poulose , David Brazdil , kernel-team@android.com Subject: [PATCH v2 1/2] arm64: Make the Meltdown mitigation state available Date: Fri, 4 Dec 2020 18:37:08 +0000 Message-Id: <20201204183709.784533-2-maz@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201204183709.784533-1-maz@kernel.org> References: <20201204183709.784533-1-maz@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, will@kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, dbarzdil@google.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Our Meltdown mitigation state isn't exposed outside of cpufeature.c, contrary to the rest of the Spectre mitigation state. As we are going to use it in KVM, expose a arm64_get_meltdown_state() helper which returns the same possible values as arm64_get_spectre_v?_state(). Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/spectre.h | 2 ++ arch/arm64/kernel/cpufeature.c | 20 +++++++++++++++++--- 2 files changed, 19 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h index fcdfbce302bd..52e788981f4a 100644 --- a/arch/arm64/include/asm/spectre.h +++ b/arch/arm64/include/asm/spectre.h @@ -29,4 +29,6 @@ bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope); void spectre_v4_enable_mitigation(const struct arm64_cpu_capabilities *__unused); void spectre_v4_enable_task_mitigation(struct task_struct *tsk); +enum mitigation_state arm64_get_meltdown_state(void); + #endif /* __ASM_SPECTRE_H */ diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 6f36c4f62f69..280b10762f6b 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -2846,14 +2846,28 @@ static int __init enable_mrs_emulation(void) core_initcall(enable_mrs_emulation); +enum mitigation_state arm64_get_meltdown_state(void) +{ + if (__meltdown_safe) + return SPECTRE_UNAFFECTED; + + if (arm64_kernel_unmapped_at_el0()) + return SPECTRE_MITIGATED; + + return SPECTRE_VULNERABLE; +} + ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) { - if (__meltdown_safe) + switch (arm64_get_meltdown_state()) { + case SPECTRE_UNAFFECTED: return sprintf(buf, "Not affected\n"); - if (arm64_kernel_unmapped_at_el0()) + case SPECTRE_MITIGATED: return sprintf(buf, "Mitigation: PTI\n"); - return sprintf(buf, "Vulnerable\n"); + default: + return sprintf(buf, "Vulnerable\n"); + } } -- 2.28.0