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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2A30EC48BF6 for ; Wed, 21 Feb 2024 14:02:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=aNwBO0RHtTTqZuc9dEg0OqNMd8wCNCSTXbIlv8YBmos=; b=V59VI32FrXA6Yt iX49SfOqDhjedcz78BhX1M88cGkhMMhIb4fma4nweBahOoGIxtX96u5PL8iT7VN8WgrAz1Ixg0wdX 5JD2aOn4FApZwOshWdw/bhm22GBkevfkiEmrLKr7k0rCV+cOaOwqGJaNvlnYINsrJfmrJaf179WAf fYB2PHwkMYjLXqO4bqoMxyHEnmfP1S0mrfMOF+zNXSmL8TjwEXvSFUaB4gbRSIhS++cQz4qEt9Bge 5OkFQ36OXKBl083q1b4ww68m88C5PIGE0C+CAO5kauz3jeXXVKclFOYL1jINuOmVfh3U5Yaj4Z/jc /LOjibeczy4zQxYBIxrw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rcnAj-00000001B21-0pwS; Wed, 21 Feb 2024 14:02:05 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rcnAg-00000001B0u-1KZz for linux-arm-kernel@lists.infradead.org; Wed, 21 Feb 2024 14:02:03 +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 D8D34FEC; Wed, 21 Feb 2024 06:02:37 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.65.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D701B3F762; Wed, 21 Feb 2024 06:01:56 -0800 (PST) Date: Wed, 21 Feb 2024 14:01:54 +0000 From: Mark Rutland To: Anshuman Khandual Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, Mark Brown , James Clark , Rob Herring , Marc Zyngier , Suzuki Poulose , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , linux-perf-users@vger.kernel.org, Oliver Upton , James Morse , kvmarm@lists.linux.dev Subject: Re: [PATCH V16 2/8] KVM: arm64: Prevent guest accesses into BRBE system registers/instructions Message-ID: References: <20240125094119.2542332-1-anshuman.khandual@arm.com> <20240125094119.2542332-3-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240125094119.2542332-3-anshuman.khandual@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240221_060202_485447_B739B2A7 X-CRM114-Status: GOOD ( 22.38 ) 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 On Thu, Jan 25, 2024 at 03:11:13PM +0530, Anshuman Khandual wrote: > Currently BRBE feature is not supported in a guest environment. This hides > BRBE feature availability via masking ID_AA64DFR0_EL1.BRBE field. Does that means that a guest can currently see BRBE advertised in the ID_AA64DFR0_EL1.BRB field, or is that hidden by the regular cpufeature code today? > This also blocks guest accesses into BRBE system registers and instructions > as if the underlying hardware never implemented FEAT_BRBE feature. > > Cc: Marc Zyngier > Cc: Oliver Upton > Cc: James Morse > Cc: Suzuki K Poulose > Cc: Catalin Marinas > Cc: Will Deacon > Cc: kvmarm@lists.linux.dev > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual > --- > Changes in V16: > > - Added BRB_INF_SRC_TGT_EL1 macro for corresponding BRB_[INF|SRC|TGT] expansion > > arch/arm64/kvm/sys_regs.c | 56 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 56 insertions(+) > > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 30253bd19917..6a06dc2f0c06 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -1304,6 +1304,11 @@ static int set_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r, > return 0; > } > > +#define BRB_INF_SRC_TGT_EL1(n) \ > + { SYS_DESC(SYS_BRBINF##n##_EL1), undef_access }, \ > + { SYS_DESC(SYS_BRBSRC##n##_EL1), undef_access }, \ > + { SYS_DESC(SYS_BRBTGT##n##_EL1), undef_access } \ With the changes suggested on the previous patch, this would need to change to be: #define BRB_INF_SRC_TGT_EL1(n) \ { SYS_DESC(SYS_BRBINF_EL1(n)), undef_access }, \ { SYS_DESC(SYS_BRBSRC_EL1(n)), undef_access }, \ { SYS_DESC(SYS_BRBTGT_EL1(n)), undef_access } \ ... which would also be easier for backporting (if necessary), since those definitions have existed for a while. Otherwise (modulo Suzuki's comment about rebasing), this looks good to me. Mark. > /* Silly macro to expand the DBG{BCR,BVR,WVR,WCR}n_EL1 registers in one go */ > #define DBG_BCR_BVR_WCR_WVR_EL1(n) \ > { SYS_DESC(SYS_DBGBVRn_EL1(n)), \ > @@ -1707,6 +1712,9 @@ static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, > /* Hide SPE from guests */ > val &= ~ID_AA64DFR0_EL1_PMSVer_MASK; > > + /* Hide BRBE from guests */ > + val &= ~ID_AA64DFR0_EL1_BRBE_MASK; > + > return val; > } > > @@ -2195,6 +2203,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { > { SYS_DESC(SYS_DC_CISW), access_dcsw }, > { SYS_DESC(SYS_DC_CIGSW), access_dcgsw }, > { SYS_DESC(SYS_DC_CIGDSW), access_dcgsw }, > + { SYS_DESC(OP_BRB_IALL), undef_access }, > + { SYS_DESC(OP_BRB_INJ), undef_access }, > > DBG_BCR_BVR_WCR_WVR_EL1(0), > DBG_BCR_BVR_WCR_WVR_EL1(1), > @@ -2225,6 +2235,52 @@ static const struct sys_reg_desc sys_reg_descs[] = { > { SYS_DESC(SYS_DBGCLAIMCLR_EL1), trap_raz_wi }, > { SYS_DESC(SYS_DBGAUTHSTATUS_EL1), trap_dbgauthstatus_el1 }, > > + /* > + * BRBE branch record sysreg address space is interleaved between > + * corresponding BRBINF_EL1, BRBSRC_EL1, and BRBTGT_EL1. > + */ > + BRB_INF_SRC_TGT_EL1(0), > + BRB_INF_SRC_TGT_EL1(16), > + BRB_INF_SRC_TGT_EL1(1), > + BRB_INF_SRC_TGT_EL1(17), > + BRB_INF_SRC_TGT_EL1(2), > + BRB_INF_SRC_TGT_EL1(18), > + BRB_INF_SRC_TGT_EL1(3), > + BRB_INF_SRC_TGT_EL1(19), > + BRB_INF_SRC_TGT_EL1(4), > + BRB_INF_SRC_TGT_EL1(20), > + BRB_INF_SRC_TGT_EL1(5), > + BRB_INF_SRC_TGT_EL1(21), > + BRB_INF_SRC_TGT_EL1(6), > + BRB_INF_SRC_TGT_EL1(22), > + BRB_INF_SRC_TGT_EL1(7), > + BRB_INF_SRC_TGT_EL1(23), > + BRB_INF_SRC_TGT_EL1(8), > + BRB_INF_SRC_TGT_EL1(24), > + BRB_INF_SRC_TGT_EL1(9), > + BRB_INF_SRC_TGT_EL1(25), > + BRB_INF_SRC_TGT_EL1(10), > + BRB_INF_SRC_TGT_EL1(26), > + BRB_INF_SRC_TGT_EL1(11), > + BRB_INF_SRC_TGT_EL1(27), > + BRB_INF_SRC_TGT_EL1(12), > + BRB_INF_SRC_TGT_EL1(28), > + BRB_INF_SRC_TGT_EL1(13), > + BRB_INF_SRC_TGT_EL1(29), > + BRB_INF_SRC_TGT_EL1(14), > + BRB_INF_SRC_TGT_EL1(30), > + BRB_INF_SRC_TGT_EL1(15), > + BRB_INF_SRC_TGT_EL1(31), > + > + /* Remaining BRBE sysreg addresses space */ > + { SYS_DESC(SYS_BRBCR_EL1), undef_access }, > + { SYS_DESC(SYS_BRBFCR_EL1), undef_access }, > + { SYS_DESC(SYS_BRBTS_EL1), undef_access }, > + { SYS_DESC(SYS_BRBINFINJ_EL1), undef_access }, > + { SYS_DESC(SYS_BRBSRCINJ_EL1), undef_access }, > + { SYS_DESC(SYS_BRBTGTINJ_EL1), undef_access }, > + { SYS_DESC(SYS_BRBIDR0_EL1), undef_access }, > + > { SYS_DESC(SYS_MDCCSR_EL0), trap_raz_wi }, > { SYS_DESC(SYS_DBGDTR_EL0), trap_raz_wi }, > // DBGDTR[TR]X_EL0 share the same encoding > -- > 2.25.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel