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=-15.5 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,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 AEBA2C433DB for ; Mon, 22 Mar 2021 22:23:00 +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 33AE3619A3 for ; Mon, 22 Mar 2021 22:23:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 33AE3619A3 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-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:Cc:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=VT+0GKoDRxgKkQ+PuqQQPHm2cjG4kBytmOq010OkI60=; b=PdLbexySJbYjF8W0YCAIgkOc/ SP8ctncRAow5UAaVpCo09gRwXcyyKaTubWykG64w+gj3M/gJWR2OOKCR/sLU/m+O2SFurf4FT4CIr Qi9obFnk2uSWSW4VjnXDaFrOW4ruCwyBN2vg8Teju/40nLSOYqc9P9qbJYPksAOHWXR0ZQnaqNF7V g5OonmkOR0nMh/zeR8qYKa58ocKEYGUctFPgBVri8pY9osw+r32AOzt6NrgBrvbjB4gsHTgZkOXic CJGVA/uj9BluS6yD2lvhCfHnQb9tHo7CNGDjDgEnQPRRLtgQrYlITLXxqaN/sIzlf3T8p3bQJ/BiM F5JpcLgPw==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lOSvI-00CgoD-Ji; Mon, 22 Mar 2021 22:21:20 +0000 Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lOSvB-00Cgn3-Sr for linux-arm-kernel@lists.infradead.org; Mon, 22 Mar 2021 22:21:16 +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 651DE1042; Mon, 22 Mar 2021 15:21:11 -0700 (PDT) Received: from [10.57.55.187] (unknown [10.57.55.187]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D35DE3F719; Mon, 22 Mar 2021 15:21:09 -0700 (PDT) Subject: Re: [PATCH v4 03/19] kvm: arm64: Hide system instruction access to Trace registers To: linux-arm-kernel@lists.infradead.org, Will Deacon , Catalin Marinas Cc: linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org, mike.leach@linaro.org, anshuman.khandual@arm.com, leo.yan@linaro.org, Marc Zyngier , Mark Rutland References: <20210225193543.2920532-1-suzuki.poulose@arm.com> <20210225193543.2920532-4-suzuki.poulose@arm.com> From: Suzuki K Poulose Message-ID: <6b8dbaed-654f-3079-bc38-ef18c0effd79@arm.com> Date: Mon, 22 Mar 2021 22:21:08 +0000 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.16; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210225193543.2920532-4-suzuki.poulose@arm.com> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210322_222114_234067_2ED20486 X-CRM114-Status: GOOD ( 21.40 ) 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Will, Catalin, On 25/02/2021 19:35, Suzuki K Poulose wrote: > 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 > --- > New patch > --- > 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, > }; > Are you happy to pick this patch for 5.12 as a fix ? Suzuki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel