Re: [PATCH v7 1/4] RISC-V: KVM: Support runtime configuration for per-VM's HGATP mode

[Radim Krčmář]

2026-04-02T21:23:00+08:00, <fangyu.yu@xxxxxxxxxxxxxxxxx>:
> From: Fangyu Yu <fangyu.yu@xxxxxxxxxxxxxxxxx>
>
> Introduces one per-VM architecture-specific fields to support runtime
> configuration of the G-stage page table format:
>
> - kvm->arch.pgd_levels: the corresponding number of page table levels
>   for the selected mode.
>
> These fields replace the previous global variables
> kvm_riscv_gstage_mode and kvm_riscv_gstage_pgd_levels, enabling different
> virtual machines to independently select their G-stage page table format
> instead of being forced to share the maximum mode detected by the kernel
> at boot time.
>
> Signed-off-by: Fangyu Yu <fangyu.yu@xxxxxxxxxxxxxxxxx>
> Reviewed-by: Andrew Jones <andrew.jones@xxxxxxxxxxxxxxxx>
> Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
> Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
> ---
> diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
> @@ -199,7 +199,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>  		r = KVM_USER_MEM_SLOTS;
>  		break;
>  	case KVM_CAP_VM_GPA_BITS:
> -		r = kvm_riscv_gstage_gpa_bits;
> +		r = kvm_riscv_gstage_gpa_bits(kvm->arch.pgd_levels);

kvm_vm_ioctl_check_extension() also gets called from with kvm == NULL
from kvm_dev_ioctl().  I think we can continue to return
...(kvm_riscv_gstage_max_pgd_levels) in that case.

Thanks.