Re: [PATCH] RISC-V: KVM: Redirect instruction access fault trap to guest

[Quan Zhou]

On 2024/8/29 14:20, zhouquan@xxxxxxxxxxx wrote:
> From: Quan Zhou <zhouquan@xxxxxxxxxxx>
>
> The M-mode redirects an unhandled instruction access
> fault trap back to S-mode when not delegating it to
> VS-mode(hedeleg). However, KVM running in HS-mode
> terminates the VS-mode software when back from M-mode.
>
> The KVM should redirect the trap back to VS-mode, and
> let VS-mode trap handler decide the next step.
>
> Signed-off-by: Quan Zhou <zhouquan@xxxxxxxxxxx>
> ---
>   arch/riscv/kvm/vcpu_exit.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index fa98e5c024b2..696b62850d0b 100644
> --- a/arch/riscv/kvm/vcpu_exit.c
> +++ b/arch/riscv/kvm/vcpu_exit.c
> @@ -182,6 +182,7 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
>   	ret = -EFAULT;
>   	run->exit_reason = KVM_EXIT_UNKNOWN;
>   	switch (trap->scause) {
> +	case EXC_INST_ACCESS:

A gentle ping, the instruction access fault should be redirected to
VS-mode for handling, is my understanding correct?

>   	case EXC_INST_ILLEGAL:
>   	case EXC_LOAD_MISALIGNED:
>   	case EXC_STORE_MISALIGNED:
>
> base-commit: 7c626ce4bae1ac14f60076d00eafe71af30450ba