From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 82ECC2D238F; Thu, 1 Oct 2026 16:29:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790872172; cv=none; b=OrFJCq+g1+FYnoiDZa+UM5iOQm5mzSo2ECjcsm2g4Qg9Ffl30qYTTSDm43uWGt/sBktCVW4z1DfP0qm/ivZTfcGL7pawe2RxLzUWjcc6atCeyPmFnfKnAx9GfodvI59oy9wV2/wHQeAfsdpHKzhJpRCSDKXwQ20eh9JDYUUh6aE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790872172; c=relaxed/simple; bh=7AIf8lTnSPZzMKd0ZIklYylTiiYQOR4tFoz57vWUuLw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=l3AVxO1r1fjZ8fXDWhCqu+s8wuaTEcnV4t0Xb7xdhSklgSDvtGcPIQyW9F57UUSyZaGac5SxGq/xp8O6BcV0ejjnsTPZxP0uIbjInm8sofI7Q355+woN4fXV4DIyZl/RJxkHxDeImOig18RnpyK+hTR/481dSbkp/VRioBHeYoE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FwIgQsS4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FwIgQsS4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1013C1F000FF; Thu, 1 Oct 2026 16:29:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790872171; bh=BuUbaFBNSrrB8IgOuIPv+TnQNAwEe+8kiRexfQtDWws=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=FwIgQsS42B0bEij1RkBtFxKf/q9IqBVPCfs5ZSeyrhmmPKCQ0E8t1btz3XQ9NY9qi iREcH6z61mzhKSaAQ1B1aysUfFlK80C0ReRx4J/IxrVeFA7EA2jhe8UrJIR9KUKjYa s2drbqjpR/7OD9iYXYIvUv8oBuTWTfSjxlYcX2hchs2k49dj6Ra1Ta7syj5tB0eGOA RY6pGWVxQlbSfaPVLvVLIYXnsab0A1LBxeyQqkCbpV8e0wR1w814h7/1W4p2to03mg nFDEnCHe6sb1gflLnbbXBl2uDBhvrOvjetdUlRF5RzY2pWmsSspFSYkEkOj1ftZHba lMrNHquOnVThA== Date: Thu, 1 Oct 2026 17:29:24 +0100 From: "Lorenzo Stoakes (ARM)" To: Mark Brown Cc: Catalin Marinas , Will Deacon , Marc Zyngier , Joey Gouly , Suzuki K Poulose , Shuah Khan , Oliver Upton , Fuad Tabba , Peter Maydell , Leonardo Bras , Wei-Lin Chang , Yao Yuan , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v21 09/15] KVM: arm64: Allow GCS to be enabled for guests Message-ID: References: <20260930-arm64-gcs-v21-0-3556644cd927@kernel.org> <20260930-arm64-gcs-v21-9-3556644cd927@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260930-arm64-gcs-v21-9-3556644cd927@kernel.org> On Wed, Sep 30, 2026 at 10:48:19PM +0100, Mark Brown wrote: > Now that required functionality for GCS is in place expose > ID_AA64PFR1_EL1.GCS, allowing guests to be given the feature. > > Reviewed-by: Leonardo Bras > Signed-off-by: Mark Brown This looks straightforward and sensible so: Reviewed-by: Lorenzo Stoakes (ARM) > --- > arch/arm64/kvm/nested.c | 3 +-- > arch/arm64/kvm/sys_regs.c | 5 +++-- > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c > index 3c4fc566eafc..f62d9ab7f31c 100644 > --- a/arch/arm64/kvm/nested.c > +++ b/arch/arm64/kvm/nested.c > @@ -1702,11 +1702,10 @@ u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val) > break; > > case SYS_ID_AA64PFR1_EL1: > - /* Only support BTI, SSBS, CSV2_frac */ > + /* Only support GCS, BTI, SSBS, CSV2_frac */ > val &= ~(ID_AA64PFR1_EL1_PFAR | > ID_AA64PFR1_EL1_MTEX | > ID_AA64PFR1_EL1_THE | > - ID_AA64PFR1_EL1_GCS | > ID_AA64PFR1_EL1_MTE_frac | > ID_AA64PFR1_EL1_NMI | > ID_AA64PFR1_EL1_SME | > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index faecf4657ec5..5de4ba1bef6b 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -2193,10 +2193,12 @@ static u64 sanitise_id_aa64pfr1_el1(const struct kvm_vcpu *vcpu, u64 val) > SYS_FIELD_GET(ID_AA64PFR0_EL1, RAS, pfr0) == ID_AA64PFR0_EL1_RAS_IMP)) > val &= ~ID_AA64PFR1_EL1_RAS_frac; > > + if (!system_supports_gcs()) > + val &= ~ID_AA64PFR1_EL1_GCS; > + > val &= ~ID_AA64PFR1_EL1_SME; > val &= ~ID_AA64PFR1_EL1_RNDR_trap; > val &= ~ID_AA64PFR1_EL1_NMI; > - val &= ~ID_AA64PFR1_EL1_GCS; > val &= ~ID_AA64PFR1_EL1_THE; > val &= ~ID_AA64PFR1_EL1_MTEX; > val &= ~ID_AA64PFR1_EL1_PFAR; > @@ -3444,7 +3446,6 @@ static const struct sys_reg_desc sys_reg_descs[] = { > ~(ID_AA64PFR1_EL1_PFAR | > ID_AA64PFR1_EL1_MTEX | > ID_AA64PFR1_EL1_THE | > - ID_AA64PFR1_EL1_GCS | > ID_AA64PFR1_EL1_MTE_frac | > ID_AA64PFR1_EL1_NMI | > ID_AA64PFR1_EL1_RNDR_trap | > > -- > 2.47.3 > > -- Cheers, Lorenzo