From patchwork Thu Nov 10 01:53:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13038223 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 E8E9FC43217 for ; Thu, 10 Nov 2022 01:54:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232378AbiKJBye (ORCPT ); Wed, 9 Nov 2022 20:54:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232134AbiKJBy1 (ORCPT ); Wed, 9 Nov 2022 20:54:27 -0500 Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A88D5B860; Wed, 9 Nov 2022 17:54:26 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1668045261; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=e4NKzeDtoFaN8kBUL712bSOeRfxgXb7x1ONm16Q4y+o=; b=r+LeK2mnGqElNPkM/9TRPhVOvTFfQU8Rq0YfxxyXVdeML0jqbULDujWLfU8U1jjDWCD4C2 bVcdvjUU6nvu6U93vhCJgsXxxiFjIGkI2iLdiUr8nLHnlO2oEX2LmV4/c/k87TwZDZINUN A0g7LwBg2Bp+kUYlRQ7hek5somRyq2I= From: Oliver Upton To: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Oliver Upton , Catalin Marinas , Will Deacon , Paolo Bonzini Cc: Raghavendra Rao Ananta , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: [RFC PATCH 2/3] KVM: arm64: Allow userspace to trap SMCCC sub-ranges Date: Thu, 10 Nov 2022 01:53:26 +0000 Message-Id: <20221110015327.3389351-3-oliver.upton@linux.dev> In-Reply-To: <20221110015327.3389351-1-oliver.upton@linux.dev> References: <20221110015327.3389351-1-oliver.upton@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org As the SMCCC (and related specifications) march towards an 'everything and the kitchen sink' interface for interacting with a system, it is less likely that KVM will implement every supported feature. Add a capability that allows userspace to trap hypercall ranges, allowing the VMM to mix-and-match between calls handled in userspace vs. KVM. Signed-off-by: Oliver Upton --- arch/arm64/include/asm/kvm_host.h | 5 ++++ arch/arm64/include/uapi/asm/kvm.h | 15 ++++++++++ arch/arm64/kvm/arm.c | 10 +++++++ arch/arm64/kvm/hypercalls.c | 48 +++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 5 files changed, 79 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index e33ed7c09a28..cc3872f1900c 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -52,6 +52,9 @@ #define KVM_HAVE_MMU_RWLOCK +#define KVM_ARM_USER_HYPERCALL_FLAGS \ + GENMASK_ULL(KVM_ARM_USER_HYPERCALL_FLAGS_COUNT - 1, 0) + /* * Mode of operation configurable with kvm-arm.mode early param. * See Documentation/admin-guide/kernel-parameters.txt for more information. @@ -104,11 +107,13 @@ struct kvm_arch_memory_slot { /** * struct kvm_smccc_features: Descriptor of the hypercall services exposed to the guests * + * @user_trap_bmap: Bitmap of SMCCC function ranges trapped to userspace * @std_bmap: Bitmap of standard secure service calls * @std_hyp_bmap: Bitmap of standard hypervisor service calls * @vendor_hyp_bmap: Bitmap of vendor specific hypervisor service calls */ struct kvm_smccc_features { + unsigned long user_trap_bmap; unsigned long std_bmap; unsigned long std_hyp_bmap; unsigned long vendor_hyp_bmap; diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index 316917b98707..07fa3f597e61 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -370,6 +370,21 @@ enum { #endif }; +enum { + KVM_ARM_USER_HYPERCALL_OWNER_ARCH = 0, + KVM_ARM_USER_HYPERCALL_OWNER_CPU = 1, + KVM_ARM_USER_HYPERCALL_OWNER_SIP = 2, + KVM_ARM_USER_HYPERCALL_OWNER_OEM = 3, + KVM_ARM_USER_HYPERCALL_OWNER_STANDARD = 4, + KVM_ARM_USER_HYPERCALL_OWNER_STANDARD_HYP = 5, + KVM_ARM_USER_HYPERCALL_OWNER_VENDOR_HYP = 6, + KVM_ARM_USER_HYPERCALL_OWNER_TRUSTED_APP = 7, + KVM_ARM_USER_HYPERCALL_OWNER_TRUSTED_OS = 8, +#ifdef __KERNEL__ + KVM_ARM_USER_HYPERCALL_FLAGS_COUNT, +#endif +}; + /* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0 #define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1 diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 6f0b56e7f8c7..6e8a222fc295 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -100,6 +100,13 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, r = 0; set_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags); break; + case KVM_CAP_ARM_USER_HYPERCALLS: + if (cap->args[0] & ~KVM_ARM_USER_HYPERCALL_FLAGS) + return -EINVAL; + + r = 0; + kvm->arch.smccc_feat.user_trap_bmap = cap->args[0]; + break; default: r = -EINVAL; break; @@ -285,6 +292,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_ARM_PTRAUTH_GENERIC: r = system_has_full_ptr_auth(); break; + case KVM_CAP_ARM_USER_HYPERCALLS: + r = KVM_ARM_USER_HYPERCALL_FLAGS; + break; default: r = 0; } diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index 62ce45d0d957..22a23b12201d 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -92,6 +92,49 @@ static bool kvm_hvc_call_default_allowed(u32 func_id) } } +static bool kvm_hvc_call_user_trapped(struct kvm_vcpu *vcpu, u32 func_id) +{ + struct kvm *kvm = vcpu->kvm; + unsigned long *bmap = &kvm->arch.smccc_feat.user_trap_bmap; + + switch (ARM_SMCCC_OWNER_NUM(func_id)) { + case ARM_SMCCC_OWNER_ARCH: + return test_bit(KVM_ARM_USER_HYPERCALL_OWNER_ARCH, bmap); + case ARM_SMCCC_OWNER_CPU: + return test_bit(KVM_ARM_USER_HYPERCALL_OWNER_CPU, bmap); + case ARM_SMCCC_OWNER_SIP: + return test_bit(KVM_ARM_USER_HYPERCALL_OWNER_SIP, bmap); + case ARM_SMCCC_OWNER_OEM: + return test_bit(KVM_ARM_USER_HYPERCALL_OWNER_OEM, bmap); + case ARM_SMCCC_OWNER_STANDARD: + return test_bit(KVM_ARM_USER_HYPERCALL_OWNER_STANDARD, bmap); + case ARM_SMCCC_OWNER_STANDARD_HYP: + return test_bit(KVM_ARM_USER_HYPERCALL_OWNER_STANDARD_HYP, bmap); + case ARM_SMCCC_OWNER_VENDOR_HYP: + return test_bit(KVM_ARM_USER_HYPERCALL_OWNER_VENDOR_HYP, bmap); + case ARM_SMCCC_OWNER_TRUSTED_APP ... ARM_SMCCC_OWNER_TRUSTED_APP_END: + return test_bit(KVM_ARM_USER_HYPERCALL_OWNER_TRUSTED_APP, bmap); + case ARM_SMCCC_OWNER_TRUSTED_OS ... ARM_SMCCC_OWNER_TRUSTED_OS_END: + return test_bit(KVM_ARM_USER_HYPERCALL_OWNER_TRUSTED_OS, bmap); + default: + return false; + } +} + +static void kvm_hvc_prepare_user_trap(struct kvm_vcpu *vcpu) +{ + struct kvm_run *run = vcpu->run; + + run->exit_reason = KVM_EXIT_HYPERCALL; + run->hypercall.nr = smccc_get_function(vcpu); + run->hypercall.args[0] = smccc_get_arg(vcpu, 1); + run->hypercall.args[1] = smccc_get_arg(vcpu, 2); + run->hypercall.args[2] = smccc_get_arg(vcpu, 3); + run->hypercall.args[3] = smccc_get_arg(vcpu, 4); + run->hypercall.args[4] = smccc_get_arg(vcpu, 5); + run->hypercall.args[5] = smccc_get_arg(vcpu, 6); +} + static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id) { struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; @@ -128,6 +171,11 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) u32 feature; gpa_t gpa; + if (kvm_hvc_call_user_trapped(vcpu, func_id)) { + kvm_hvc_prepare_user_trap(vcpu); + return 0; + } + if (!kvm_hvc_call_allowed(vcpu, func_id)) goto out; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 0d5d4419139a..ea6c1983a545 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1178,6 +1178,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_S390_ZPCI_OP 221 #define KVM_CAP_S390_CPU_TOPOLOGY 222 #define KVM_CAP_DIRTY_LOG_RING_ACQ_REL 223 +#define KVM_CAP_ARM_USER_HYPERCALLS 224 #ifdef KVM_CAP_IRQ_ROUTING