From nobody Fri Apr 3 09:29:01 2026 Received: from out30-118.freemail.mail.aliyun.com (out30-118.freemail.mail.aliyun.com [115.124.30.118]) (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 6C2B2313527; Thu, 2 Apr 2026 13:23:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.118 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775136213; cv=none; b=p0K49B1N5FZiJn21KT85iWx/46bSQyPykxreAW+Th2+I7rzscf1ZAdYcX20uqkKPBYq5+1jDZ4tHsqAttuqvZ0k0nCTDsxi+lFEqjfjBc5HmKIhH68pIffM3TfOihi6s4dsYDPFIfAekHOKyDKXtR3kM8RpekSYhlkmZrjdPYH8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775136213; c=relaxed/simple; bh=vEVhbhJQfbtkQWiZeTnkivUuuywK6DDaznDvkOiAxKM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=mh7hYjLyn/4yr8jfvnXnFQ7n3E5OFmjd7GXfekZCZqDaxWMvrug/M34DHRThYNipwUCeqtoYfBrrCPTije6sU2eejZNtRQLXScWpZZ+oJu3MWSn/ltgzdXjgQt2e/cbAiJ42Lm1DVWascqWU3IPy5D120gtdptDjAuLR9XorxBM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=v7ajNs5+; arc=none smtp.client-ip=115.124.30.118 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="v7ajNs5+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1775136209; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=uQ7MH/P5X4dEeg6SQT8ncWdhiILNQuCxIsZxQBjBQDo=; b=v7ajNs5+1Av0MMYLI2fsLoLxlmbm7pcXmUba2WeYvTR3cJXN3Wji1yKBk1WOAdqEMCCwCR9+yjwSy+Dua+qXwalojo6gUtS2tKAVgS/0Zo5/V54CpxNPkhj9Rag4owYsscslw83UFnfhuK5/oF9dRmUYsPPwC/2boe7jabiLAAE= X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam011083073210;MF=fangyu.yu@linux.alibaba.com;NM=1;PH=DS;RN=18;SR=0;TI=SMTPD_---0X0HNDF6_1775136206; Received: from localhost.localdomain(mailfrom:fangyu.yu@linux.alibaba.com fp:SMTPD_---0X0HNDF6_1775136206 cluster:ay36) by smtp.aliyun-inc.com; Thu, 02 Apr 2026 21:23:26 +0800 From: fangyu.yu@linux.alibaba.com To: pbonzini@redhat.com, corbet@lwn.net, anup@brainfault.org, atish.patra@linux.dev, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, skhan@linuxfoundation.org Cc: guoren@kernel.org, radim.krcmar@oss.qualcomm.com, andrew.jones@oss.qualcomm.com, linux-doc@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Fangyu Yu Subject: [PATCH v7 4/4] RISC-V: KVM: add KVM_CAP_RISCV_SET_HGATP_MODE Date: Thu, 2 Apr 2026 21:23:03 +0800 Message-Id: <20260402132303.6252-5-fangyu.yu@linux.alibaba.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20260402132303.6252-1-fangyu.yu@linux.alibaba.com> References: <20260402132303.6252-1-fangyu.yu@linux.alibaba.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Fangyu Yu Add a VM capability that allows userspace to select the G-stage page table format by setting HGATP.MODE on a per-VM basis. Userspace enables the capability via KVM_ENABLE_CAP, passing the requested HGATP.MODE in args[0]. The request is rejected with -EINVAL if the mode is not supported by the host, and with -EBUSY if the VM has already been committed (e.g. vCPUs have been created or any memslot is populated). KVM_CHECK_EXTENSION(KVM_CAP_RISCV_SET_HGATP_MODE) returns a bitmask of the HGATP.MODE formats supported by the host. Signed-off-by: Fangyu Yu Reviewed-by: Andrew Jones Reviewed-by: Guo Ren --- Documentation/virt/kvm/api.rst | 27 +++++++++++++++++++++++++++ arch/riscv/kvm/vm.c | 18 ++++++++++++++++-- include/uapi/linux/kvm.h | 1 + 3 files changed, 44 insertions(+), 2 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 032516783e96..9d7f6958fa81 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -8902,6 +8902,33 @@ helpful if user space wants to emulate instructions = which are not This capability can be enabled dynamically even if VCPUs were already created and are running. =20 +7.47 KVM_CAP_RISCV_SET_HGATP_MODE +--------------------------------- + +:Architectures: riscv +:Type: VM +:Parameters: args[0] contains the requested HGATP mode +:Returns: + - 0 on success. + - -EINVAL if args[0] is outside the range of HGATP modes supported by the + hardware. + - -EBUSY if vCPUs have already been created for the VM, if the VM has any + non-empty memslots. + +This capability allows userspace to explicitly select the HGATP mode for +the VM. The selected mode must be supported by both KVM and hardware. This +capability must be enabled before creating any vCPUs or memslots. + +If this capability is not enabled, KVM will select the default HGATP mode +automatically. The default is the highest HGATP.MODE value supported by +hardware. + +``KVM_CHECK_EXTENSION(KVM_CAP_RISCV_SET_HGATP_MODE)`` returns a bitmask of +HGATP.MODE values supported by the host. A return value of 0 indicates that +the capability is not supported. Supported-mode bitmask use HGATP.MODE +encodings as defined by the RISC-V privileged specification, such as Sv39x4 +corresponds to HGATP.MODE=3D8, so userspace should test bitmask & BIT(8). + 8. Other capabilities. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c index 4d82a886102c..5e82a3ad3ad0 100644 --- a/arch/riscv/kvm/vm.c +++ b/arch/riscv/kvm/vm.c @@ -201,6 +201,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long = ext) case KVM_CAP_VM_GPA_BITS: r =3D kvm_riscv_gstage_gpa_bits(kvm->arch.pgd_levels); break; + case KVM_CAP_RISCV_SET_HGATP_MODE: + r =3D kvm_riscv_get_hgatp_mode_mask(); + break; default: r =3D 0; break; @@ -211,12 +214,23 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, lon= g ext) =20 int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) { + if (cap->flags) + return -EINVAL; + switch (cap->cap) { case KVM_CAP_RISCV_MP_STATE_RESET: - if (cap->flags) - return -EINVAL; kvm->arch.mp_state_reset =3D true; return 0; + case KVM_CAP_RISCV_SET_HGATP_MODE: + if (!kvm_riscv_hgatp_mode_is_valid(cap->args[0])) + return -EINVAL; + + if (kvm->created_vcpus || !kvm_are_all_memslots_empty(kvm)) + return -EBUSY; +#ifdef CONFIG_64BIT + kvm->arch.pgd_levels =3D 3 + cap->args[0] - HGATP_MODE_SV39X4; +#endif + return 0; default: return -EINVAL; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 80364d4dbebb..a74a80fd4046 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -989,6 +989,7 @@ struct kvm_enable_cap { #define KVM_CAP_ARM_SEA_TO_USER 245 #define KVM_CAP_S390_USER_OPEREXEC 246 #define KVM_CAP_S390_KEYOP 247 +#define KVM_CAP_RISCV_SET_HGATP_MODE 248 =20 struct kvm_irq_routing_irqchip { __u32 irqchip; --=20 2.50.1