From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6C6CF19DF4F; Wed, 1 Oct 2025 11:06:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759316761; cv=none; b=RMb9tDc7h26h/KUyLJJXjJouZOy2kelHE4QGQI1skDdtJKUD9cAiGAYtPUYHRjNkscMONwJjO1qbf0MjjDOq9oWDuA/Bhl4JBAN7J90Nf/LtkvJu2Jzq5BArEuIPICVS+B9KhyQihA/039TKfzyES3LcdEKMXcqV4F6OYnXxfyE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759316761; c=relaxed/simple; bh=BBQTY11uPcvv9rvZ3xpgazdEbhNoa7n1ec1bbV18sIk=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=nXcs2HKpCa//S5WLhyOd150VcAE0N2b8rmjSZWv/Ut5zXB1r3M7ptPhnI4oB6sh7t5BuaC/bjrbPbCQSFI5aItsQkrcwwsffNvqlsnw/V948xEBh6wYqxm9T9GRIPTz3p6HBinA7ew61gI5p7KRk5K0YnURbV/0+1eTZE2CYjTU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fO5S/ltQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fO5S/ltQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D19A4C4CEF4; Wed, 1 Oct 2025 11:06:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759316761; bh=BBQTY11uPcvv9rvZ3xpgazdEbhNoa7n1ec1bbV18sIk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fO5S/ltQCfJbMtQ6/ZUyMaSOM6TbHn3SBVMfywlHB9NeL1YHyjF5tLPSpc5XQ3rop SKku27McJ+bfiTFkcX9LDFyjSeFp6xvQ69OOZaVZmudG5qLL3w0NBWuGB3ckCwm8zl VRZs3g69e2F6E724KnFiZux7FRE93kcbpsBjRqGjuvuOCNwZ6ZulDA6OJ9Ib1/f6KB Dz9VsaAE6iNvA0FPInNtD0d/d/SPJcVZLr26kUaUkPr/1V4VMJhKcK+sxlvznxME9Z ZxhGYbH04e5IMm5WCZ9mNN1K23lVLVU/1kIzyXdBUTCnOIYMZ+JKEJtEz7cCoKEqeh 2mouohLM6mL0Q== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1v3uek-0000000AmO3-29VK; Wed, 01 Oct 2025 11:05:58 +0000 Date: Wed, 01 Oct 2025 12:05:58 +0100 Message-ID: <86ms6azxt5.wl-maz@kernel.org> From: Marc Zyngier To: Steven Price Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, Catalin Marinas , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , 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 Subject: Re: [PATCH v10 05/43] arm64: RME: Check for RME support at KVM init In-Reply-To: <20250820145606.180644-6-steven.price@arm.com> References: <20250820145606.180644-1-steven.price@arm.com> <20250820145606.180644-6-steven.price@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: steven.price@arm.com, kvm@vger.kernel.org, kvmarm@lists.linux.dev, catalin.marinas@arm.com, will@kernel.org, james.morse@arm.com, oliver.upton@linux.dev, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, joey.gouly@arm.com, alexandru.elisei@arm.com, christoffer.dall@arm.com, tabba@google.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, gshan@redhat.com, sdonthineni@nvidia.com, alpergun@google.com, aneesh.kumar@kernel.org, fj0570is@fujitsu.com, vannapurve@google.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Wed, 20 Aug 2025 15:55:25 +0100, Steven Price wrote: > > Query the RMI version number and check if it is a compatible version. A > static key is also provided to signal that a supported RMM is available. > > Functions are provided to query if a VM or VCPU is a realm (or rec) > which currently will always return false. > > Later patches make use of struct realm and the states as the ioctls > interfaces are added to support realm and REC creation and destruction. > > Reviewed-by: Gavin Shan > Reviewed-by: Suzuki K Poulose > Signed-off-by: Steven Price > --- > Changes since v8: > * No need to guard kvm_init_rme() behind 'in_hyp_mode'. > Changes since v6: > * Improved message for an unsupported RMI ABI version. > Changes since v5: > * Reword "unsupported" message from "host supports" to "we want" to > clarify that 'we' are the 'host'. > Changes since v2: > * Drop return value from kvm_init_rme(), it was always 0. > * Rely on the RMM return value to identify whether the RSI ABI is > compatible. > --- > arch/arm64/include/asm/kvm_emulate.h | 18 +++++++++ > arch/arm64/include/asm/kvm_host.h | 4 ++ > arch/arm64/include/asm/kvm_rme.h | 56 ++++++++++++++++++++++++++++ > arch/arm64/include/asm/virt.h | 1 + > arch/arm64/kvm/Makefile | 2 +- > arch/arm64/kvm/arm.c | 5 +++ > arch/arm64/kvm/rme.c | 56 ++++++++++++++++++++++++++++ > 7 files changed, 141 insertions(+), 1 deletion(-) > create mode 100644 arch/arm64/include/asm/kvm_rme.h > create mode 100644 arch/arm64/kvm/rme.c > > diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h > index fa8a08a1ccd5..ab4093e41c4b 100644 > --- a/arch/arm64/include/asm/kvm_emulate.h > +++ b/arch/arm64/include/asm/kvm_emulate.h > @@ -674,4 +674,22 @@ static inline void vcpu_set_hcrx(struct kvm_vcpu *vcpu) > vcpu->arch.hcrx_el2 |= HCRX_EL2_SCTLR2En; > } > } > + > +static inline bool kvm_is_realm(struct kvm *kvm) > +{ > + if (static_branch_unlikely(&kvm_rme_is_available) && kvm) Under what circumstances would you call this with a NULL pointer? > + return kvm->arch.is_realm; > + return false; > +} > + > +static inline enum realm_state kvm_realm_state(struct kvm *kvm) > +{ > + return READ_ONCE(kvm->arch.realm.state); > +} > + > +static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu) > +{ > + return false; > +} > + > #endif /* __ARM64_KVM_EMULATE_H__ */ > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 2f2394cce24e..d1511ce26191 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 > @@ -404,6 +405,9 @@ struct kvm_arch { > * the associated pKVM instance in the hypervisor. > */ > struct kvm_protected_vm pkvm; > + > + bool is_realm; > + struct realm realm; Given that pkvm and CCA are pretty much exclusive, I don't think we need to store both states separately. Make those a union. > }; > > struct kvm_vcpu_fault_info { > diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h > new file mode 100644 > index 000000000000..9c8a0b23e0e4 > --- /dev/null > +++ b/arch/arm64/include/asm/kvm_rme.h > @@ -0,0 +1,56 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Copyright (C) 2023 ARM Ltd. > + */ > + > +#ifndef __ASM_KVM_RME_H > +#define __ASM_KVM_RME_H None of that is about RME. This is about CCA, which is purely a SW construct, and not a CPU architecture feature. So 's/rme/cca/' everywhere that describe something that is not a direct effect of FEAT_RME being implemented on the CPU, but instead something that is CCA-specific. > + > +/** > + * enum realm_state - State of a Realm > + */ > +enum realm_state { > + /** > + * @REALM_STATE_NONE: > + * Realm has not yet been created. rmi_realm_create() may be > + * called to create the realm. > + */ > + REALM_STATE_NONE, > + /** > + * @REALM_STATE_NEW: > + * Realm is under construction, not eligible for execution. Pages > + * may be populated with rmi_data_create(). > + */ > + 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, > + /** > + * @REALM_STATE_DYING: > + * Realm is in the process of being destroyed or has already been > + * destroyed. > + */ > + REALM_STATE_DYING, > + /** > + * @REALM_STATE_DEAD: > + * Realm has been destroyed. > + */ > + REALM_STATE_DEAD > +}; > + > +/** > + * struct realm - Additional per VM data for a Realm > + * > + * @state: The lifetime state machine for the realm > + */ > +struct realm { > + enum realm_state state; > +}; > + > +void kvm_init_rme(void); > + > +#endif /* __ASM_KVM_RME_H */ > diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h > index aa280f356b96..db73c9bfd8c9 100644 > --- a/arch/arm64/include/asm/virt.h > +++ b/arch/arm64/include/asm/virt.h > @@ -82,6 +82,7 @@ void __hyp_reset_vectors(void); > bool is_kvm_arm_initialised(void); > > DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized); > +DECLARE_STATIC_KEY_FALSE(kvm_rme_is_available); Same thing about RME. > > static inline bool is_pkvm_initialized(void) > { > diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile > index 3ebc0570345c..70fa017831b3 100644 > --- a/arch/arm64/kvm/Makefile > +++ b/arch/arm64/kvm/Makefile > @@ -16,7 +16,7 @@ CFLAGS_handle_exit.o += -Wno-override-init > kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \ > inject_fault.o va_layout.o handle_exit.o config.o \ > guest.o debug.o reset.o sys_regs.o stacktrace.o \ > - vgic-sys-reg-v3.o fpsimd.o pkvm.o \ > + vgic-sys-reg-v3.o fpsimd.o pkvm.o rme.o \ > arch_timer.o trng.o vmid.o emulate-nested.o nested.o at.o \ > vgic/vgic.o vgic/vgic-init.o \ > vgic/vgic-irqfd.o vgic/vgic-v2.o \ > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 888f7c7abf54..76177c56f1ef 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -40,6 +40,7 @@ > #include > #include > #include > +#include > #include > > #include > @@ -59,6 +60,8 @@ enum kvm_wfx_trap_policy { > static enum kvm_wfx_trap_policy kvm_wfi_trap_policy __read_mostly = KVM_WFX_NOTRAP_SINGLE_TASK; > static enum kvm_wfx_trap_policy kvm_wfe_trap_policy __read_mostly = KVM_WFX_NOTRAP_SINGLE_TASK; > > +DEFINE_STATIC_KEY_FALSE(kvm_rme_is_available); > + > DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector); > > DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_base); > @@ -2836,6 +2839,8 @@ static __init int kvm_arm_init(void) > > in_hyp_mode = is_kernel_in_hyp_mode(); > > + kvm_init_rme(); > + > if (cpus_have_final_cap(ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE) || > cpus_have_final_cap(ARM64_WORKAROUND_1508412)) > kvm_info("Guests without required CPU erratum workarounds can deadlock system!\n" \ > diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c > new file mode 100644 > index 000000000000..67cf2d94cb2d > --- /dev/null > +++ b/arch/arm64/kvm/rme.c > @@ -0,0 +1,56 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2023 ARM Ltd. > + */ > + > +#include > + > +#include > +#include > + > +static int rmi_check_version(void) > +{ > + struct arm_smccc_res res; > + unsigned short version_major, version_minor; > + unsigned long host_version = RMI_ABI_VERSION(RMI_ABI_MAJOR_VERSION, > + RMI_ABI_MINOR_VERSION); > + > + arm_smccc_1_1_invoke(SMC_RMI_VERSION, host_version, &res); Shouldn't you first check that RME is actually available, by looking at ID_AA64PFR0_EL1.RME? > + > + 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); > + > + kvm_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; > + } > + > + kvm_info("RMI ABI version %d.%d\n", version_major, version_minor); > + > + return 0; > +} > + > +void kvm_init_rme(void) > +{ > + if (PAGE_SIZE != SZ_4K) > + /* Only 4k page size on the host is supported */ > + return; Move the comment above the check (same thing below). M. -- Without deviation from the norm, progress is not possible.