From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DC7E74CC29C; Tue, 13 Oct 2026 09:58:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791885518; cv=none; b=EshjIGg4g9I3BFIr3k3kG6tSUvGywHjXyv+0KnhV1INsTSoXJCI0g2C+sz+Vv6kCotY0CrgE6H8wktxEMjHyNSI3U7tt2SE5au1qcgM4UaOIaSefh/Y5pAFB+xcIiB7sqMy8cu+GsOBhkMX35Yn9zDUf1XRlnKCiYBD01KkgkEU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791885518; c=relaxed/simple; bh=YXnRSTWAU7IyxFtbn+qxY3qd2/8gPBY2gi/t/qkHSRE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Mz/YDr4JJUgUpjDsxi/ay0hIU/hBm3tFyFguvaGGDbQO64jzLO0k8DmlZ8Z1C17Erh5vyFfXw244K6g743+tKQCRi22KYEp22ugtDxx9WqFCS8AmrbrXF3ombPhIfUKs1SJYPVsjdSeT7wr3G+VG528Bv3bwP/L1Yhzv6LWPH78= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=gyrI4p+h; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="gyrI4p+h" 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 E5801169C; Tue, 13 Oct 2026 02:58:30 -0700 (PDT) Received: from [10.0.128.125] (Suzukis-MBP.cambridge.arm.com [10.0.128.125]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 587BB3F7B4; Tue, 13 Oct 2026 02:58:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1791885514; bh=YXnRSTWAU7IyxFtbn+qxY3qd2/8gPBY2gi/t/qkHSRE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=gyrI4p+h+rg7F7KzN+FY9x9PiD8fijVdOLYuXXJRTseA4OxfHLYYokao4JrlWWDYc b7TYUZxc1LcIIzSY473gSneYG1BQKVdJSIpkJWp2/mAll6ueBdVaaSiIzgjq0dfLc6 n/vn/bnmlNaqC9t2P2EbLNHqMRTHnuTppuDBHw80= Message-ID: <8be050e3-8af1-4f04-902f-9bc01b209dd0@arm.com> Date: Tue, 13 Oct 2026 10:58:29 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v22 02/10] firmware: arm_rmm: Check for RMI support at init Content-Language: en-GB To: Gavin Shan , kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: maz@kernel.org, will@kernel.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, steven.price@arm.com, aneesh.kumar@kernel.org, oupton@kernel.org, joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, sdonthineni@nvidia.com, alpergun@google.com, fj0570is@fujitsu.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org, enju.kohei@fujitsu.com, sudeep.holla@arm.com, jonathan.cameron@oss.qualcomm.com References: <20261002061507.1600269-1-suzuki.poulose@arm.com> <20261002061507.1600269-3-suzuki.poulose@arm.com> <2586e689-c27d-4e4c-8c69-03e24259cb96@redhat.com> From: Suzuki K Poulose In-Reply-To: <2586e689-c27d-4e4c-8c69-03e24259cb96@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 13/10/2026 04:53, Gavin Shan wrote: > Hi Suzuki, > > On 10/2/26 4:14 PM, Suzuki K Poulose wrote: >> From: Steven Price >> >> Query the RMI version number and check if it is a compatible version. >> All RMM feature registers are read and exposed for future code to >> use. Also restrict the support to SMC conduit. >> >> We only support this for Little Endian kernels, the Big Endian kernel >> support is anyway marked BROKEN and is being removed. >> >> Cc: Marc Zyngier >> Cc: Oliver Upton >> Reviewed-by: Jonathan Cameron >> Reviewed-by: Gavin Shan >> Reviewed-by: Catalin Marinas >> Tested-by: Gavin Shan >> Signed-off-by: Steven Price >> Co-developed-by: Suzuki K Poulose >> Signed-off-by: Suzuki K Poulose >> --- > > [...] > >> --- >>   MAINTAINERS                       |   2 + >>   arch/arm64/Kconfig                |   1 + >>   arch/arm64/kernel/cpufeature.c    |   1 + >>   arch/arm64/kvm/sys_regs.c         |   2 + >>   drivers/firmware/Kconfig          |   1 + >>   drivers/firmware/Makefile         |   1 + >>   drivers/firmware/arm_rmm/Kconfig  |  25 +++++++ >>   drivers/firmware/arm_rmm/Makefile |   1 + >>   drivers/firmware/arm_rmm/rmi.c    | 112 ++++++++++++++++++++++++++++++ >>   include/linux/arm-rmi-cmds.h      |  48 +++++++++++++ >>   10 files changed, 194 insertions(+) >>   create mode 100644 drivers/firmware/arm_rmm/Kconfig >>   create mode 100644 drivers/firmware/arm_rmm/Makefile >>   create mode 100644 drivers/firmware/arm_rmm/rmi.c >>   create mode 100644 include/linux/arm-rmi-cmds.h >> > > [...] > >> diff --git a/drivers/firmware/arm_rmm/rmi.c b/drivers/firmware/ >> arm_rmm/rmi.c >> new file mode 100644 >> index 0000000000000..06f5392c982d2 >> --- /dev/null >> +++ b/drivers/firmware/arm_rmm/rmi.c >> @@ -0,0 +1,112 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Copyright (C) 2023-2026 ARM Ltd. >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> + >> +#include >> +#include >> + >> +/* RMM v2.0 defines RmiFeatureRegister0 to RmiFeatureRegister4. */ >> +static unsigned long rmi_feat_reg_cache[5] __ro_after_init; >> + >> +static int rmi_check_version(void) >> +{ >> +    unsigned short version_major, version_minor; >> +    unsigned long host_version = RMI_ABI_VERSION(RMI_ABI_MAJOR_VERSION, >> +                             RMI_ABI_MINOR_VERSION); >> +    unsigned long aa64pfr0 = >> read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1); >> +    struct arm_smccc_1_2_regs res = { >> +        SMC_RMI_VERSION, host_version, >> +    }; >> + >> +    /* If RME isn't supported, then RMI can't be */ >> +    if (cpuid_feature_extract_unsigned_field(aa64pfr0, >> ID_AA64PFR0_EL1_RME_SHIFT) == 0) >> +        return -ENXIO; >> + >> +    if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_SMC) >> +        return -ENXIO; > > I think we need to ensure SMCCC version is v1.2 or a newer one here? > arm_smccc_1_2_smc() > is immediately called by rmi_smccc_invoke() after this check. > >     if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_SMC || >             arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2) We could. But I am wondering if that adds any value ? If the RMM exists and responds to the RMI_ABI_VERSION, it must be so on a platform with v1.2 or greater ? The extra check doesn't hurt. Suzuki >         return -ENXIO; > > Thanks, > Gavin > >> + >> +    rmi_smccc_invoke(&res); >> +    if (res.a0 == SMCCC_RET_NOT_SUPPORTED) >> +        return -ENXIO; >> + >> +    version_major = RMI_ABI_VERSION_GET_MAJOR(res.a1); >> +    version_minor = RMI_ABI_VERSION_GET_MINOR(res.a1); >> + >> +    if (res.a0 != RMI_SUCCESS) { >> +        unsigned short high_version_major, high_version_minor; >> + >> +        high_version_major = RMI_ABI_VERSION_GET_MAJOR(res.a2); >> +        high_version_minor = RMI_ABI_VERSION_GET_MINOR(res.a2); >> + >> +        pr_err("Unsupported RMI ABI (v%d.%d - v%d.%d) we want v%d.%d\n", >> +               version_major, version_minor, >> +               high_version_major, high_version_minor, >> +               RMI_ABI_MAJOR_VERSION, >> +               RMI_ABI_MINOR_VERSION); >> +        return -ENXIO; >> +    } >> + >> +    pr_info("RMI ABI version %d.%d\n", version_major, version_minor); >> + >> +    return 0; >> +} >> + > > [...] > > >