From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0F8ED606A328 for ; Thu, 5 Nov 2026 15:12:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=uI/XK9rw; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=I9yJWYMO DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=IWJD0iHItHJ0ZLICudpIGPh2lKAzMkhjEJ2bZxXwT1g=; b=uI/XK9rw/A+1f8 zha5/xB87K65kvP9Nj4BiNe3FYQ6vkWIHeJPheZnTQ01tSVOqWyVVbMU/tGbe7qdiytQPmDNGtJOM kyZlNE2prCcX3q6FtmnY6k2pYm5c1QR8gAswAMQsEI2j65tUhl2AnbYFdoJZYXk3FgVvzj0Up6pBC ctU9N18VJcmjbLc/uP5hGJSy/YZ4AietKMeq8B7E3cjg5SZyfGg/xODBFNq33uBDGIQqHuQZ975BE ZN2rmxyLAHN1xUNhCNlQTkMOvVNhoq+rV0deAZclP+qG4VFssXtlqAqQHnfnqwQ59GViYDiJxJ13D VhCqh3f20yJNutZVZKhw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOz8s-00000009NTI-0veZ; Thu, 05 Nov 2026 15:12:42 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOz8e-00000009NPU-2TFg for linux-arm-kernel@lists.infradead.org; Thu, 05 Nov 2026 15:12:31 +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 9E02B16F2; Thu, 5 Nov 2026 07:12:24 -0800 (PST) Received: from [10.0.128.250] (e122027.cambridge.arm.com [10.0.128.250]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D24EC3F628; Thu, 5 Nov 2026 07:12:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793891547; bh=K05vKtM+fPDTzjogjywixfTKzhfzKJwvrbfn/flAQKU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=I9yJWYMOEfAXqlqdwyFVq2M5GIwutk5K6psqq9Cpc7QM5j08Mcw18ktYr7AnqST3/ GjFIAmD16GvgTjVNYKV0YLBzFCCAvPxZyKsBXJAoSEfd1Vp0+12u1UwKcGhCWb1cWp eDOuw2QPcrF8XLvPwDKHxwX3Bkyl6a8Ir0NoK4TQ= Message-ID: Date: Thu, 5 Nov 2026 15:12:23 +0000 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 04/11] KVM: arm64: CCA: Check for LPA2 support and SHA-256 To: Suzuki K Poulose , kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve , WeiLin.Chang@arm.com, Lorenzo Pieralisi References: <20261102141304.126883-1-steven.price@arm.com> <20261102141304.126883-5-steven.price@arm.com> From: Steven Price Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261105_071229_547618_6739AD34 X-CRM114-Status: GOOD ( 21.33 ) X-Spam-Score: -4.4 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 03/11/2026 11:47, Suzuki K Poulose wrote: > Hi Steven > > On 02/11/2026 14:12, Steven Price wrote: >> If KVM has enabled LPA2 support then check that the RMM also supports >> it. If there is a mismatch then disable support for realm guests as the >> VMM may attempt to create a guest which is incompatible with the RMM. >> >> Also check for SHA-256 support in the RMM as to begin with we only >> support SHA-256 based measurements. This can be relaxed in the future. > > > This could be merged with the patch 3. Makes sense. > >> >> Reviewed-by: Suzuki K Poulose >> Signed-off-by: Steven Price > > >> --- >>   arch/arm64/kvm/rmi.c | 25 +++++++++++++++++++++++++ >>   1 file changed, 25 insertions(+) >> >> diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c >> index 9d118768550d..5b07beff8bc9 100644 >> --- a/arch/arm64/kvm/rmi.c >> +++ b/arch/arm64/kvm/rmi.c >> @@ -6,8 +6,30 @@ >>   #include >>   #include >>   +#include >>   #include >>   +static bool rmi_has_feature(int reg, unsigned long feature) >> +{ >> +    return !!u64_get_bits(rmi_feat_reg(reg), feature); >> +} >> + > > minor nit: Do we see this useful for others (e.g., DA) ? May be we could > move this to the include/linux/arm-rmi-cmds.h ? > > May be we could even make the above a macro, something like > > > #define rmi_has_feature(reg, feat) >     u64_get_bits(rmi_feat_reg(reg), RMI_FEATURE_REGISTER_#reg _#feat) > Sashiko pointed out that my use of u64_get_bits() is problematic. So I'll fix that up and more it to the header file. Thanks, Steve > > Cheers > Suzuki > >> +static int rmm_check_features(void) >> +{ >> +    if (kvm_lpa2_is_enabled() && >> +        !rmi_has_feature(0, RMI_FEATURE_REGISTER_0_LPA2)) { >> +        kvm_err("RMM doesn't support LPA2\n"); >> +        return -ENXIO; >> +    } >> + >> +    if (!rmi_has_feature(1, RMI_FEATURE_REGISTER_1_HASH_SHA_256)) { >> +        kvm_err("RMM doesn't support SHA-256 measurements\n"); >> +        return -ENXIO; >> +    } >> + >> +    return 0; >> +} >> + >>   void kvm_init_rmi(void) >>   { >>       if (kvm_get_mode() != KVM_MODE_RMM) >> @@ -16,5 +38,8 @@ void kvm_init_rmi(void) >>       if (!is_rmi_available()) >>           return; >>   +    if (rmm_check_features()) >> +        return; >> + >>       /* Future patch will enable static branch kvm_rmi_is_available */ >>   } >