linux-kernel - Re: [PATCH v2] RISC-V: KVM: add KVM_CAP_RISCV_SET_HGATP_MODE

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Message-ID: <6txqxrkyqh4afmked4hdi6qekkqrb54ar3q5upz3ennnuaktsi@dtoarqt7e26t>
Date: Fri, 16 Jan 2026 13:03:23 -0600
From: Andrew Jones <andrew.jones@....qualcomm.com>
To: fangyu.yu@...ux.alibaba.com
Cc: pbonzini@...hat.com, corbet@....net, anup@...infault.org,
        atish.patra@...ux.dev, pjw@...nel.org, palmer@...belt.com,
        aou@...s.berkeley.edu, alex@...ti.fr, guoren@...nel.org,
        ajones@...tanamicro.com, rkrcmar@...tanamicro.com,
        linux-doc@...r.kernel.org, kvm@...r.kernel.org,
        kvm-riscv@...ts.infradead.org, linux-riscv@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] RISC-V: KVM: add KVM_CAP_RISCV_SET_HGATP_MODE

On Mon, Jan 05, 2026 at 10:32:32PM +0800, fangyu.yu@...ux.alibaba.com wrote:
...
> +	case KVM_CAP_RISCV_SET_HGATP_MODE:
> +#ifdef CONFIG_64BIT
> +		if (cap->args[0] < HGATP_MODE_SV39X4 ||
> +			cap->args[0] > kvm_riscv_gstage_max_mode)
> +			return -EINVAL;
> +		if (kvm->arch.gstage_mode_initialized)
> +			return 0;
> +		kvm->arch.gstage_mode_initialized = true;
> +		kvm->arch.kvm_riscv_gstage_mode = cap->args[0];
> +		kvm->arch.kvm_riscv_gstage_pgd_levels = 3 +
> +		    kvm->arch.kvm_riscv_gstage_mode - HGATP_MODE_SV39X4;
> +		kvm_info("using SV%lluX4 G-stage page table format\n",
> +			39 + (cap->args[0] - HGATP_MODE_SV39X4) * 9);

I don't think we want this kvm_info line, particularly if it doesn't also
include a VM ID in some form to allow readers to know which VM is using
the selected format. Let's either drop it or change it to kvm_debug and
include a VM ID.

Thanks,
drew

> +#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
> 
> 
> -- 
> kvm-riscv mailing list
> kvm-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/kvm-riscv

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