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 6A3F337E5F5; Tue, 6 Oct 2026 05:10:59 +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=1791263461; cv=none; b=ERDmqL2Toi9z89cmOwzz4P3bRaSkaZc2LxvDp0lj1RJsj/cOcRHNVbTYUWuJ/fIpJV1aociGWg/RiJ34Ip9C7f/4gY+FaS3XgoNdOfg4pVUtlG4/BJXlO2ITF5OjGQBzQWG0PwLds7bxDj3a+6ofaiSWe4qeeRdjTobEY7ItSIA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791263461; c=relaxed/simple; bh=7sWLZyvocBVUSF6JTvcAYmYuD+V3OBaqBlyyA8q87dM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cMPhP+mZGMWRCtoeUbwyL5MJWV2Hpc86KxIjAOg0nUj3sr2D4b2YGcFzVS3Wufd2wShExdmjIR7SUYo7EBF8660dPBxjza8KiUQ+6nemT2MJxYrKDYtTdv9qoVMeI3SuQaFsJNQngocb6SLMqf00g39yliYZQkiBm2mfNls/nIk= 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=cr88Q/26; 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="cr88Q/26" 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 6E68C1595; Mon, 5 Oct 2026 22:10:55 -0700 (PDT) Received: from [10.57.10.233] (unknown [10.57.10.233]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 23C9E3F763; Mon, 5 Oct 2026 22:10:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1791263458; bh=7sWLZyvocBVUSF6JTvcAYmYuD+V3OBaqBlyyA8q87dM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=cr88Q/26bT5Gh0PWAt9WHvtulW0F+N5GaLp/2i8swPFTfns4uo4cGLiUjssbfagej eYbOgFbtChwzqnpd+EF4c8+hxKZPy4G2eQut0NNFdH/kuMN93NB2hZWotCH5dFrZmk coZi9q3WXVFj5qIkj3MDPjMZdf/yW0wqyg8tPPys= Message-ID: <05dbdd69-411f-40e2-a7fa-8651ce2a2556@arm.com> Date: Tue, 6 Oct 2026 07:10:53 +0200 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 18/23] KVM: arm64: CCA: Introduce Realms 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: <20261005090754.2140522-1-suzuki.poulose@arm.com> <20261005090754.2140522-19-suzuki.poulose@arm.com> <9bbb3b3c-522f-4deb-9f32-0fcf731dd0bb@redhat.com> From: Suzuki K Poulose In-Reply-To: <9bbb3b3c-522f-4deb-9f32-0fcf731dd0bb@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 06/10/2026 04:42, Gavin Shan wrote: > On 10/5/26 7:07 PM, Suzuki K Poulose wrote: >> From: Steven Price >> >> Add foundational work for supporting Realms. >>   - Add a new VM flavor. >>   - At KVM init, check if the KVM can support Realms (though not >> functional >>     yet) and will be advertised by static key kvm_rmi_is_available. This >>     will be turned on in a later patches, once we have all the bits and >>     pieces ready. For now check if we are blessed with KVM_MODE_RMM. >>   - Add realm specific tracking in kvm_arch. Since Realm and protected >> pKVM >>     states are mutually exclusive, move them into a union. >> >> Please note that we cannot create Realm VMs yet. This requires further >> changes to the UABI and core RMI driver support, which will come later. >> >> Reviewed-by: Jonathan Cameron >> Signed-off-by: Steven Price >> Co-developed-by: Suzuki K Poulose >> Signed-off-by: Suzuki K Poulose >> --- >>   arch/arm64/include/asm/kvm_emulate.h | 16 ++++++++ >>   arch/arm64/include/asm/kvm_host.h    | 19 ++++++--- >>   arch/arm64/include/asm/kvm_rmi.h     | 61 ++++++++++++++++++++++++++++ >>   arch/arm64/include/asm/virt.h        |  1 + >>   arch/arm64/kvm/Makefile              |  2 +- >>   arch/arm64/kvm/arm.c                 |  6 +++ >>   arch/arm64/kvm/mmu.c                 |  1 + >>   arch/arm64/kvm/rmi.c                 | 18 ++++++++ >>   8 files changed, 118 insertions(+), 6 deletions(-) >>   create mode 100644 arch/arm64/include/asm/kvm_rmi.h >>   create mode 100644 arch/arm64/kvm/rmi.c >> >> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/ >> include/asm/kvm_emulate.h >> index a3c1928bdf743..d360a8b05b8bf 100644 >> --- a/arch/arm64/include/asm/kvm_emulate.h >> +++ b/arch/arm64/include/asm/kvm_emulate.h >> @@ -793,4 +793,20 @@ static inline void kvm_reset_vcpu_psci(struct >> kvm_vcpu *vcpu, >>       vcpu_set_reg(vcpu, 0, reset_state->r0); >>   } >> +static inline enum realm_state kvm_realm_state(struct kvm *kvm) >> +{ >> +    return READ_ONCE(kvm->arch.realm.state); >> +} >> + >> +static inline void kvm_set_realm_state(struct kvm *kvm, >> +                       enum realm_state new_state) >> +{ >> +    WRITE_ONCE(kvm->arch.realm.state, new_state); >> +} >> + >> +static inline bool kvm_realm_is_created(struct kvm *kvm) >> +{ >> +    return kvm_vm_is_realm(kvm) && kvm_realm_state(kvm) != >> REALM_STATE_NONE; >> +} >> + >>   #endif /* __ARM64_KVM_EMULATE_H__ */ >> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/ >> asm/kvm_host.h >> index dfa9d4ec61a76..3debffef638a4 100644 >> --- a/arch/arm64/include/asm/kvm_host.h >> +++ b/arch/arm64/include/asm/kvm_host.h >> @@ -27,6 +27,7 @@ >>   #include >>   #include >>   #include >> +#include >>   #include >>   #define __KVM_HAVE_ARCH_INTC_INITIALIZED >> @@ -334,6 +335,7 @@ enum kvm_arm_vm_flavor { >>       VM_PKVM,        /* Normal guests on pKVM */ >>       MARKER(__VM_PROTECTED), >>       VM_PROTECTED_PKVM,    /* Protected VM */ >> +    VM_REALM,        /* CCA */ >>       VM_FLAVOR_MAX >>   }; >> @@ -450,11 +452,14 @@ struct kvm_arch { >>       /* Count the number of VNCR_EL2 TLBs */ >>       atomic_t vncr_tlb_count; >> -    /* >> -     * For an untrusted host VM, 'pkvm.handle' is used to lookup >> -     * the associated pKVM instance in the hypervisor. >> -     */ >> -    struct kvm_protected_vm pkvm; >> +    union { >> +        /* >> +         * For an untrusted host VM, 'pkvm.handle' is used to lookup >> +         * the associated pKVM instance in the hypervisor. >> +         */ >> +        struct kvm_protected_vm pkvm; >> +        struct realm realm; >> +    }; >>   #ifdef CONFIG_PTDUMP_STAGE2_DEBUGFS >>       /* Nested virtualization info */ >> @@ -1565,6 +1570,10 @@ struct kvm *kvm_arch_alloc_vm(void); >>           (__kvm && kvm_vm_is_protected_pkvm(__kvm));        \ >>       }) >> + >> +#define kvm_vm_is_realm(kvm)        ((kvm)->arch.vm_flavor == VM_REALM) >> +#define vcpu_is_rec(vcpu)        kvm_vm_is_realm((vcpu)->kvm) >> + > > vcpu_is_rec() isn't safely called in nVHE hyp stub. So do we need add > something > similiar to what we had for vcpu_is_protected(vcpu) in PATCH[05]? > > #ifdef __KVM_NVHE_HYPERVISOR__ > /* vcpu_is_rec() isn't expected to called in nVHE hyp stub */ > #define vcpu_is_rec(vcpu)    BUILD_BUG_ON(1) > #else > #define vcpu_is_rec(vcpu)    kvm_vm_is_realm((vcpu)->kvm) > #endif > > >>   #define kvm_vm_hyp_is_distrusting(kvm)    ((kvm)->arch.vm_flavor >= >> __VM_DISTRUSTING_HYP) >>   int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature); >> diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/ >> asm/kvm_rmi.h >> new file mode 100644 >> index 0000000000000..44f5c75a27b5b >> --- /dev/null >> +++ b/arch/arm64/include/asm/kvm_rmi.h >> @@ -0,0 +1,61 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* >> + * Copyright (C) 2023-2026 ARM Ltd. >> + */ >> + >> +#ifndef __ASM_KVM_RMI_H >> +#define __ASM_KVM_RMI_H >> + >> +/** >> + * enum realm_state - State of a Realm >> + * >> + * Mirrors the RMM's Realm lifecycle states where they are meaningful >> to KVM, >> + * with REALM_STATE_DYING being a KVM-internal state used to prevent >> further >> + * requests while teardown is in progress. KVM does not track >> REALM_SYSTEM_OFF >> + * or REALM_ZOMBIE separately as they naturally lead to teardown. >> + */ >> +enum realm_state { >> +    /** >> +     * @REALM_STATE_NONE: >> +     *      Realm has not yet been created. rmi_realm_create() has not >> +     *      yet been called. >> +     */ >> +    REALM_STATE_NONE, >> +    /** >> +     * @REALM_STATE_NEW: >> +     *      Realm is under construction, rmi_realm_create() has been >> +     *      called, but it is not yet activated. Pages may be populated. >                                                      ^^^^^ > Granule instead of page is the term applicable to RMM. Lets use a generic > term 'memory' here. Also, lets mention the name of the function used to > populate the memory (granules), which is consistent to the comments for > REALM_STATE_ACTIVE. > >     Memory may be populated by rmi_rtt_data_map_init(). > > >> +     */ >> +    REALM_STATE_NEW, >> +    /** >> +     * @REALM_STATE_ACTIVE: >> +     *      Realm has been created and is eligible for execution with >> +     *      rmi_rec_enter(). Pages may no longer be populated with >> +     *      rmi_data_create(). >> +     */ >> +    REALM_STATE_ACTIVE, > > rmi_data_create() is an invalid function name. > >     Memory can't longer be populated using rmi_rtt_data_map_init(). Ack, thanks for spotting, I will fix them. Cheers Suzuki