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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2D8FC7EE2D for ; Wed, 1 Mar 2023 11:55:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229775AbjCALzk (ORCPT ); Wed, 1 Mar 2023 06:55:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35300 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229736AbjCALzh (ORCPT ); Wed, 1 Mar 2023 06:55:37 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 77FAC3C78D; Wed, 1 Mar 2023 03:55:32 -0800 (PST) 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 5B3152F4; Wed, 1 Mar 2023 03:56:15 -0800 (PST) Received: from [10.57.16.41] (unknown [10.57.16.41]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E39BE3F587; Wed, 1 Mar 2023 03:55:28 -0800 (PST) Message-ID: <6a2c0db1-a8c8-1c21-5b14-e12067ad3ead@arm.com> Date: Wed, 1 Mar 2023 11:55:25 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [RFC PATCH 07/28] arm64: kvm: Allow passing machine type in KVM creation Content-Language: en-GB To: Zhi Wang Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, Catalin Marinas , Marc Zyngier , 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 References: <20230127112248.136810-1-suzuki.poulose@arm.com> <20230127112932.38045-1-steven.price@arm.com> <20230127112932.38045-8-steven.price@arm.com> <20230213183530.00006d35@gmail.com> From: Steven Price In-Reply-To: <20230213183530.00006d35@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/02/2023 16:35, Zhi Wang wrote: > On Fri, 27 Jan 2023 11:29:11 +0000 > Steven Price wrote: > >> Previously machine type was used purely for specifying the physical >> address size of the guest. Reserve the higher bits to specify an ARM >> specific machine type and declare a new type 'KVM_VM_TYPE_ARM_REALM' >> used to create a realm guest. >> >> Signed-off-by: Steven Price >> --- >> arch/arm64/kvm/arm.c | 13 +++++++++++++ >> arch/arm64/kvm/mmu.c | 3 --- >> arch/arm64/kvm/reset.c | 3 --- >> include/uapi/linux/kvm.h | 19 +++++++++++++++---- >> 4 files changed, 28 insertions(+), 10 deletions(-) >> >> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c >> index 50f54a63732a..badd775547b8 100644 >> --- a/arch/arm64/kvm/arm.c >> +++ b/arch/arm64/kvm/arm.c >> @@ -147,6 +147,19 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) >> { >> int ret; >> >> + if (type & ~(KVM_VM_TYPE_ARM_MASK | KVM_VM_TYPE_ARM_IPA_SIZE_MASK)) >> + return -EINVAL; >> + >> + switch (type & KVM_VM_TYPE_ARM_MASK) { >> + case KVM_VM_TYPE_ARM_NORMAL: >> + break; >> + case KVM_VM_TYPE_ARM_REALM: >> + kvm->arch.is_realm = true; > > It is better to let this call fail when !kvm_rme_is_available? It is > strange to be able to create a VM with REALM type in a system doesn't > support RME. Good point - I'll add a check here. Thanks, Steve >> + break; >> + default: >> + return -EINVAL; >> + } >> + >> ret = kvm_share_hyp(kvm, kvm + 1); >> if (ret) >> return ret; >> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c >> index d0f707767d05..22c00274884a 100644 >> --- a/arch/arm64/kvm/mmu.c >> +++ b/arch/arm64/kvm/mmu.c >> @@ -709,9 +709,6 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t >> u64 mmfr0, mmfr1; >> u32 phys_shift; >> >> - if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK) >> - return -EINVAL; >> - >> phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type); >> if (is_protected_kvm_enabled()) { >> phys_shift = kvm_ipa_limit; >> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c >> index c165df174737..9e71d69e051f 100644 >> --- a/arch/arm64/kvm/reset.c >> +++ b/arch/arm64/kvm/reset.c >> @@ -405,9 +405,6 @@ int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type) >> if (kvm_is_realm(kvm)) >> ipa_limit = kvm_realm_ipa_limit(); >> >> - if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK) >> - return -EINVAL; >> - >> phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type); >> if (phys_shift) { >> if (phys_shift > ipa_limit || >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index fec1909e8b73..bcfc4d58dc19 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -898,14 +898,25 @@ struct kvm_ppc_resize_hpt { >> #define KVM_S390_SIE_PAGE_OFFSET 1 >> >> /* >> - * On arm64, machine type can be used to request the physical >> - * address size for the VM. Bits[7-0] are reserved for the guest >> - * PA size shift (i.e, log2(PA_Size)). For backward compatibility, >> - * value 0 implies the default IPA size, 40bits. >> + * On arm64, machine type can be used to request both the machine type and >> + * the physical address size for the VM. >> + * >> + * Bits[11-8] are reserved for the ARM specific machine type. >> + * >> + * Bits[7-0] are reserved for the guest PA size shift (i.e, log2(PA_Size)). >> + * For backward compatibility, value 0 implies the default IPA size, 40bits. >> */ >> +#define KVM_VM_TYPE_ARM_SHIFT 8 >> +#define KVM_VM_TYPE_ARM_MASK (0xfULL << KVM_VM_TYPE_ARM_SHIFT) >> +#define KVM_VM_TYPE_ARM(_type) \ >> + (((_type) << KVM_VM_TYPE_ARM_SHIFT) & KVM_VM_TYPE_ARM_MASK) >> +#define KVM_VM_TYPE_ARM_NORMAL KVM_VM_TYPE_ARM(0) >> +#define KVM_VM_TYPE_ARM_REALM KVM_VM_TYPE_ARM(1) >> + >> #define KVM_VM_TYPE_ARM_IPA_SIZE_MASK 0xffULL >> #define KVM_VM_TYPE_ARM_IPA_SIZE(x) \ >> ((x) & KVM_VM_TYPE_ARM_IPA_SIZE_MASK) >> + >> /* >> * ioctls for /dev/kvm fds: >> */ >