From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-113.freemail.mail.aliyun.com (out30-113.freemail.mail.aliyun.com [115.124.30.113]) (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 1C65038DF9; Mon, 26 Jan 2026 01:26:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.113 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769390767; cv=none; b=TwXkZpg3cc0po5IIyLcWTDCo9eMFhuSxe82kuAwYOOGkdd9H3qw9eRSBbYA+WzJa2+V98OAChYEiusJupet+45/4Yt0+diiLbwOgy5fG0hLUt3c/X59q+nO6rTbNNzZJfH2dAVLB7WbN0ACIAVqWPSeLxx2J7Xj+aulsQBipN7Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769390767; c=relaxed/simple; bh=Yb+JP07ijQn7cCb91p7u5ScNQqG1qvqytVfflQQb5SE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=td8TYE9olcPBM+cEA+J2keS9aYJjmS6sh8EbHCV2CknslQVN+scI17xT8u6FyQOyfqJEPl4sspTbOcBA5NeZDAtCK1huYpvb/UN3X60kFliZrqmPvKPB7rbG/SwA6BevjfEH6dh1+xMmhRQOlJhrnuzWQOIikZa7+Px5d+gTMkI= 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=mT9+RuJ+; arc=none smtp.client-ip=115.124.30.113 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="mT9+RuJ+" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1769390756; h=From:To:Subject:Date:Message-Id:MIME-Version:Content-Type; bh=gCARNgGUNLhCd1rBcVoXKGTchR8utjxKY5PDBVlWowc=; b=mT9+RuJ+dE2lBCVbMGH1jgRMsyN8jLeg5/XdxzWjfqp6V3dy8SV6E9im1q9/XX5+pHqMJg3uTaD6m6Z6s46iC7zn28DoCJ1r5mqPj7Rti1gY9vjsX33+yNgX/UxBEp7ni++/jHb2dsbZrRafg6xHj0USifklf19p0we2CIJsY84= Received: from localhost.localdomain(mailfrom:fangyu.yu@linux.alibaba.com fp:SMTPD_---0WxmmVCv_1769390752 cluster:ay36) by smtp.aliyun-inc.com; Mon, 26 Jan 2026 09:25:54 +0800 From: fangyu.yu@linux.alibaba.com To: fangyu.yu@linux.alibaba.com Cc: ajones@ventanamicro.com, alex@ghiti.fr, andrew.jones@oss.qualcomm.com, anup@brainfault.org, aou@eecs.berkeley.edu, atish.patra@linux.dev, corbet@lwn.net, guoren@kernel.org, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, palmer@dabbelt.com, pbonzini@redhat.com, pjw@kernel.org, radim.krcmar@oss.qualcomm.com Subject: Re: [PATCH v3 2/2] RISC-V: KVM: add KVM_CAP_RISCV_SET_HGATP_MODE Date: Mon, 26 Jan 2026 09:25:50 +0800 Message-Id: <20260126012550.38206-1-fangyu.yu@linux.alibaba.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20260125150450.27068-3-fangyu.yu@linux.alibaba.com> References: <20260125150450.27068-3-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-Type: text/plain; charset=y Content-Transfer-Encoding: 8bit >From: Fangyu Yu > >This capability allows userspace to explicitly select the HGATP mode >for the VM. The selected mode must be less than or equal to the max >HGATP mode supported by the hardware. This capability must be enabled >before creating any vCPUs, and can only be set once per VM. > >Signed-off-by: Fangyu Yu >--- > Documentation/virt/kvm/api.rst | 18 ++++++++++++++++++ > arch/riscv/kvm/vm.c | 26 ++++++++++++++++++++++++-- > include/uapi/linux/kvm.h | 1 + > 3 files changed, 43 insertions(+), 2 deletions(-) > >diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst >index 01a3abef8abb..9d0794b174c7 100644 >--- a/Documentation/virt/kvm/api.rst >+++ b/Documentation/virt/kvm/api.rst >@@ -8765,6 +8765,24 @@ 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. > >+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, or if the capability has already been set for the VM. >+ >+This capability allows userspace to explicitly select the HGATP mode for >+the VM. The selected mode must be less than or equal to the maximum HGATP >+mode supported by the hardware. This capability must be enabled before >+creating any vCPUs, and can only be set once per VM. >+ Hi Andrew: In v3，no changes were made here, as KVM_CAP_RISCV_SET_HGATP_MODE might be appropriate, just like the no5lvl and no4lvl in the kernel. If you think it's needed, I'm happy to discuss this further. Thanks, Fangyu > 8. Other capabilities. > ====================== > >diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c >index 4b2156df40fc..7bc9b193dcaa 100644 >--- a/arch/riscv/kvm/vm.c >+++ b/arch/riscv/kvm/vm.c >@@ -202,6 +202,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_VM_GPA_BITS: > r = kvm_riscv_gstage_gpa_bits(&kvm->arch); > break; >+ case KVM_CAP_RISCV_SET_HGATP_MODE: >+ r = IS_ENABLED(CONFIG_64BIT) ? 1 : 0; >+ break; > default: > r = 0; > break; >@@ -212,12 +215,31 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > > 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 = true; > return 0; >+ case KVM_CAP_RISCV_SET_HGATP_MODE: >+#ifdef CONFIG_64BIT >+ if (cap->args[0] < HGATP_MODE_SV39X4 || >+ cap->args[0] > kvm_riscv_gstage_mode(kvm_riscv_gstage_max_pgd_levels)) >+ return -EINVAL; >+ >+ if (kvm->arch.gstage_mode_user_initialized || kvm->created_vcpus || >+ !kvm_are_all_memslots_empty(kvm)) >+ return -EBUSY; >+ >+ kvm->arch.gstage_mode_user_initialized = true; >+ kvm->arch.kvm_riscv_gstage_pgd_levels = >+ 3 + cap->args[0] - HGATP_MODE_SV39X4; >+ kvm_debug("VM (vmid:%lu) using SV%lluX4 G-stage page table format\n", >+ kvm->arch.vmid.vmid, >+ 39 + (cap->args[0] - HGATP_MODE_SV39X4) * 9); >+#endif >+ return 0; > default: > return -EINVAL; > } >diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >index dddb781b0507..00c02a880518 100644 >--- a/include/uapi/linux/kvm.h >+++ b/include/uapi/linux/kvm.h >@@ -974,6 +974,7 @@ struct kvm_enable_cap { > #define KVM_CAP_GUEST_MEMFD_FLAGS 244 > #define KVM_CAP_ARM_SEA_TO_USER 245 > #define KVM_CAP_S390_USER_OPEREXEC 246 >+#define KVM_CAP_RISCV_SET_HGATP_MODE 247 > > struct kvm_irq_routing_irqchip { > __u32 irqchip; >-- >2.50.1