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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,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 8253AC433DB for ; Tue, 23 Mar 2021 12:08:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3742E619AE for ; Tue, 23 Mar 2021 12:08:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230295AbhCWMHg (ORCPT ); Tue, 23 Mar 2021 08:07:36 -0400 Received: from foss.arm.com ([217.140.110.172]:45030 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230316AbhCWMHL (ORCPT ); Tue, 23 Mar 2021 08:07:11 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 867D0106F; Tue, 23 Mar 2021 05:07:11 -0700 (PDT) Received: from ewhatever.cambridge.arm.com (ewhatever.cambridge.arm.com [10.1.197.1]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id F02DF3F719; Tue, 23 Mar 2021 05:07:09 -0700 (PDT) From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, coresight@lists.linaro.org, mathieu.poirier@linaro.org, mike.leach@linaro.org, leo.yan@linaro.org, anshuman.khandual@arm.com, maz@kernel.org, catalin.marinas@arm.com, Suzuki K Poulose , Will Deacon , Mark Rutland Subject: [PATCH v5 01/19] [Queued] kvm: arm64: Hide system instruction access to Trace registers Date: Tue, 23 Mar 2021 12:06:29 +0000 Message-Id: <20210323120647.454211-2-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20210323120647.454211-1-suzuki.poulose@arm.com> References: <20210323120647.454211-1-suzuki.poulose@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently we advertise the ID_AA6DFR0_EL1.TRACEVER for the guest, when the trace register accesses are trapped (CPTR_EL2.TTA == 1). So, the guest will get an undefined instruction, if trusts the ID registers and access one of the trace registers. Lets be nice to the guest and hide the feature to avoid unexpected behavior. Even though this can be done at KVM sysreg emulation layer, we do this by removing the TRACEVER from the sanitised feature register field. This is fine as long as the ETM drivers can handle the individual trace units separately, even when there are differences among the CPUs. Cc: Marc Zyngier Cc: Will Deacon Cc: Catalin Marinas Cc: Mark Rutland Signed-off-by: Suzuki K Poulose -- Note: Marc has indicated that he will be picking this patch I have included in the series for ease of testing. --- arch/arm64/kernel/cpufeature.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 066030717a4c..a4698f09bf32 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -383,7 +383,6 @@ static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = { * of support. */ S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, 0), - ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_TRACEVER_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_DEBUGVER_SHIFT, 4, 0x6), ARM64_FTR_END, }; -- 2.24.1 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,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 139DEC433E1 for ; Tue, 23 Mar 2021 12:09:31 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7273661994 for ; Tue, 23 Mar 2021 12:09:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7273661994 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=l+e/a5iBoLh3H3C80RLm8U9/vGgW0/4q8sTkfT/FgrI=; b=nmDCJNWo4DJLnKs1JToYuAXOL EhkLK2HNV19bQTQAPDTxzO8GMfCUePBjSZOC85P9869SA3FEvVDvVQiH2TiORHcr7k6DiFJkl+qfG b6yb3DSarutdST4T2KwP2fUSS8RSYk29Ie2eXlaH0VZy3Ool5ggLjZglHXiHJMXdSaN3h3wawRTy5 OPw3xUHoUlpSRiCjGttL7sHKsYc9UCFUngw3hexPNYLX5t7CYFyZBxtU9d51WCFUlC3AlM92EgUfU Uj6OXdi9TFxJA82VykndwngtvAo7xqfD1dta9WAINPviSrebsvMbMGl/0uzAJOdMp37rrxpXHQQt/ w30PcoBHQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lOfoq-00EsO4-8g; Tue, 23 Mar 2021 12:07:32 +0000 Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lOfoY-00EsIx-6g for linux-arm-kernel@lists.infradead.org; Tue, 23 Mar 2021 12:07:16 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 867D0106F; Tue, 23 Mar 2021 05:07:11 -0700 (PDT) Received: from ewhatever.cambridge.arm.com (ewhatever.cambridge.arm.com [10.1.197.1]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id F02DF3F719; Tue, 23 Mar 2021 05:07:09 -0700 (PDT) From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, coresight@lists.linaro.org, mathieu.poirier@linaro.org, mike.leach@linaro.org, leo.yan@linaro.org, anshuman.khandual@arm.com, maz@kernel.org, catalin.marinas@arm.com, Suzuki K Poulose , Will Deacon , Mark Rutland Subject: [PATCH v5 01/19] [Queued] kvm: arm64: Hide system instruction access to Trace registers Date: Tue, 23 Mar 2021 12:06:29 +0000 Message-Id: <20210323120647.454211-2-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20210323120647.454211-1-suzuki.poulose@arm.com> References: <20210323120647.454211-1-suzuki.poulose@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210323_120714_479890_2336F5E8 X-CRM114-Status: GOOD ( 11.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Currently we advertise the ID_AA6DFR0_EL1.TRACEVER for the guest, when the trace register accesses are trapped (CPTR_EL2.TTA == 1). So, the guest will get an undefined instruction, if trusts the ID registers and access one of the trace registers. Lets be nice to the guest and hide the feature to avoid unexpected behavior. Even though this can be done at KVM sysreg emulation layer, we do this by removing the TRACEVER from the sanitised feature register field. This is fine as long as the ETM drivers can handle the individual trace units separately, even when there are differences among the CPUs. Cc: Marc Zyngier Cc: Will Deacon Cc: Catalin Marinas Cc: Mark Rutland Signed-off-by: Suzuki K Poulose -- Note: Marc has indicated that he will be picking this patch I have included in the series for ease of testing. --- arch/arm64/kernel/cpufeature.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 066030717a4c..a4698f09bf32 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -383,7 +383,6 @@ static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = { * of support. */ S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, 0), - ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_TRACEVER_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_DEBUGVER_SHIFT, 4, 0x6), ARM64_FTR_END, }; -- 2.24.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel