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 04612C982CC for ; Wed, 16 Sep 2026 16:13:00 +0000 (UTC) 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-Owner; bh=tX7txk1kRxhjkNh29KOizqou/hf795jun6a8jQwOqc8=; b=H5/vOcwzRH8z8Bv4vEmA4VDiq0 wMmuoRGCfGHemiMpUBvbOvyPdpT1Ga5HdLzOn8thci/V7Adt5hxNn5y+x+2i3avu62jbBEHXNuR/z 0T1uuqdMniIWT8CVWrPda4A63nE54d+yNC5fpvh+SGsEu6/1SrhuikZViYpyHzVfvRuqGaG930eym +fVTEdGW5JS8nUpL+gL4hB4hkbEqYRaq2cJUpLsEZQ7JywcW1w5QMtHeeh73uhufr8PLrSim1uvED EAkKwfr7NbLyIyOBqW03lD+eAeHjwOKqfI+WkFNCoBzcQ0viibtaVFSCZbo4Id1vNpuzHFOWzvbsT qyCrG+Vg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6sFe-00000009hlq-0p4U; Wed, 16 Sep 2026 16:12:50 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6sFa-00000009hl6-49tx for linux-arm-kernel@lists.infradead.org; Wed, 16 Sep 2026 16:12:48 +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 42F181516; Wed, 16 Sep 2026 09:12:40 -0700 (PDT) Received: from [10.57.8.14] (unknown [10.57.8.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E18BA3F7B4; Wed, 16 Sep 2026 09:12:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789575163; bh=pjaVQE4akQZgPjv1LnRO5574aqN1CfXUHpF8mOqhjAU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Xuc9obhNrSIabA/7M5zQDGoh4O2ASYpT/smQ4VjKwml4m07SIHobscgQCxC2k6LpI 308ACacyVJyF8LdHu7EHtP25hHwUBTIfqlZnmHXp20MrWQBbU3S6er1INvrrjFJZIc JyWW3qrOKmhE9ebSEg4lvhZVY/TJl2jndtzddHi8= Message-ID: <73c921bb-9897-481d-bcb2-ef9b578a7c9f@arm.com> Date: Wed, 16 Sep 2026 17:12:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 8/9] arm64: realm: Add RHI helper to query IPA state change alignment Content-Language: en-GB To: "Aneesh Kumar K.V (Arm)" , linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev Cc: Catalin Marinas , Jason Gunthorpe , Marc Zyngier , Marek Szyprowski , Robin Murphy , Steven Price , Thomas Gleixner , Will Deacon References: <20260904103452.1197239-1-aneesh.kumar@kernel.org> <20260904103452.1197239-9-aneesh.kumar@kernel.org> From: Suzuki K Poulose In-Reply-To: <20260904103452.1197239-9-aneesh.kumar@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260916_091247_120474_6C0E0351 X-CRM114-Status: GOOD ( 28.79 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 04/09/2026 11:34, Aneesh Kumar K.V (Arm) wrote: > Arm CCA guests need to know the granularity at which the host expects IPA > state changes to be performed. This can be larger than the guest page size > and is needed when deciding the alignment for memory shared with the host. > > Add the Realm Host Interface host configuration definitions and an > get_ipa_state_change_alignment() helper. The helper uses RSI_HOST_CALL to > query the supported HostConf version and features, reads the IPA change > alignment when available, and falls back to PAGE_SIZE if the interface is > unavailable or returns an invalid value. > > Signed-off-by: Aneesh Kumar K.V (Arm) It may be worth mentioning the document number and may be the link for RHI spec. e.g., The Realm Host Interface specification Arm DEN00148 defines ... > --- > drivers/firmware/arm_rmm/rsi.c | 46 ++++++++++++++++++++++++++++++++++ > include/linux/arm-rsi-cmds.h | 10 ++++++++ > include/linux/arm-smccc-rhi.h | 25 ++++++++++++++++++ > include/linux/arm-smccc-rsi.h | 7 ++++++ > 4 files changed, 88 insertions(+) > create mode 100644 include/linux/arm-smccc-rhi.h > > diff --git a/drivers/firmware/arm_rmm/rsi.c b/drivers/firmware/arm_rmm/rsi.c > index 52f40256bd78..2cd53f82432f 100644 > --- a/drivers/firmware/arm_rmm/rsi.c > +++ b/drivers/firmware/arm_rmm/rsi.c > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > #include > #include > > @@ -164,6 +165,51 @@ static int realm_register_memory_enc_ops(void) > return arm64_mem_crypt_ops_register(&realm_crypt_ops); > } > > +/* we need an aligned struct for rsi_host_call. slab is not yet ready */ > +static struct rsi_host_call hostconf_call __initdata; > +static unsigned long __maybe_unused __init get_ipa_state_change_alignment(void) > +{ > + long ret; > + unsigned long shared_granule_size; > + > + hostconf_call.imm = 0; > + hostconf_call.gprs[0] = RHI_HOSTCONF_VERSION; Do we need to 0 out the other GPRs for RES0 arguments ? > + ret = rsi_host_call(lm_alias(&hostconf_call)); > + if (ret != RSI_SUCCESS) > + goto err_out; > + > + if (hostconf_call.gprs[0] != RHI_HOSTCONF_VER_1_0) > + goto err_out; > + > + hostconf_call.imm = 0; > + hostconf_call.gprs[0] = RHI_HOSTCONF_FEATURES; Same here, especially gprs[] could be overwritten by the results from the Host for the previous call. > + ret = rsi_host_call(lm_alias(&hostconf_call)); > + if (ret != RSI_SUCCESS) > + goto err_out; > + > + if (!(hostconf_call.gprs[0] & __RHI_HOSTCONF_GET_IPA_CHANGE_ALIGNMENT)) > + goto err_out; > + > + hostconf_call.imm = 0; > + hostconf_call.gprs[0] = RHI_HOSTCONF_GET_IPA_CHANGE_ALIGNMENT; > + ret = rsi_host_call(lm_alias(&hostconf_call)); minor nit: This patterns keep repeating. May be we could define a macro or something to make it cleaner ? > + if (ret != RSI_SUCCESS) > + goto err_out; > + > + shared_granule_size = hostconf_call.gprs[0]; > + if (shared_granule_size & (SZ_4K - 1) || > + !is_power_of_2(shared_granule_size)) > + goto err_out; > + > + return max(PAGE_SIZE, shared_granule_size); > +err_out: > + /* > + * For failure condition assume host is built with 4K page size > + * and hence IPA state change alignment can be guest PAGE_SIZE. > + */ > + return PAGE_SIZE; > +} > + > void __init arm64_rsi_init(void) > { > if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_SMC) > diff --git a/include/linux/arm-rsi-cmds.h b/include/linux/arm-rsi-cmds.h > index 3f7a6a833993..996f1621b996 100644 > --- a/include/linux/arm-rsi-cmds.h > +++ b/include/linux/arm-rsi-cmds.h > @@ -236,4 +236,14 @@ static inline unsigned long rsi_attestation_token_continue(phys_addr_t granule, > return res.a0; > } > > +static inline unsigned long rsi_host_call(struct rsi_host_call *rhi_call) > +{ > + phys_addr_t addr = virt_to_phys(rhi_call); > + struct arm_smccc_res res; > + > + arm_smccc_1_1_invoke(SMC_RSI_HOST_CALL, addr, &res); > + > + return res.a0; > +} > + > #endif /* __LINUX_ARM_RSI_CMDS_H_ */ > diff --git a/include/linux/arm-smccc-rhi.h b/include/linux/arm-smccc-rhi.h > new file mode 100644 > index 000000000000..91a29996d72d > --- /dev/null > +++ b/include/linux/arm-smccc-rhi.h > @@ -0,0 +1,25 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (C) 2026 ARM Ltd. > + */ > + > +#ifndef __LINUX_ARM_SMCCC_RHI_H_ > +#define __LINUX_ARM_SMCCC_RHI_H_ > + > +#include > + > +#define SMC_RHI_CALL(func) \ > + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ > + ARM_SMCCC_SMC_64, \ > + ARM_SMCCC_OWNER_STANDARD_HYP,\ > + (func)) > + > +#define RHI_HOSTCONF_VER_1_0 0x10000 > +#define RHI_HOSTCONF_VERSION SMC_RHI_CALL(0x004E) > + > +#define __RHI_HOSTCONF_GET_IPA_CHANGE_ALIGNMENT BIT(0) minor nit: Could this be: RHI_HOSTCONF_FEATURE_GET_IPA_CHANGE_ALIGNMENT BIT(0) to indicate this applies to the RHI_HOSTCONF_FEATURES output ? > +#define RHI_HOSTCONF_FEATURES SMC_RHI_CALL(0x004F) > + > +#define RHI_HOSTCONF_GET_IPA_CHANGE_ALIGNMENT SMC_RHI_CALL(0x0050) Cheers Suzuki > + > +#endif /* __LINUX_ARM_SMCCC_RHI_H_ */ > diff --git a/include/linux/arm-smccc-rsi.h b/include/linux/arm-smccc-rsi.h > index fddb77986f70..3532a3f08f4e 100644 > --- a/include/linux/arm-smccc-rsi.h > +++ b/include/linux/arm-smccc-rsi.h > @@ -182,6 +182,13 @@ struct realm_config { > */ > #define SMC_RSI_IPA_STATE_GET SMC_RSI_FID(0x198) > > +struct rsi_host_call { > + union { > + u16 imm; > + u64 padding0; > + }; > + u64 gprs[31]; > +} __aligned(0x100); > /* > * Make a Host call. > *