Re: [PATCH v12 25/31] LoongArch: KVM: Implement handle fpu exception

[bibo, mao]

Reviewed-by: Bibo, Mao <maobibo@xxxxxxxxxxx>

在 2023/5/30 09:52, Tianrui Zhao 写道:
> Implement handle fpu exception, using kvm_own_fpu to enable fpu for
> guest.
> 
> Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
> ---
>  arch/loongarch/kvm/exit.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
> index 1237ceb06d0c..10f9922a7e76 100644
> --- a/arch/loongarch/kvm/exit.c
> +++ b/arch/loongarch/kvm/exit.c
> @@ -631,3 +631,29 @@ static int _kvm_handle_read_fault(struct kvm_vcpu *vcpu)
>  {
>  	return _kvm_handle_mmu_fault(vcpu, false);
>  }
> +
> +/**
> + * _kvm_handle_fpu_disabled() - Guest used fpu however it is disabled at host
> + * @vcpu:	Virtual CPU context.
> + *
> + * Handle when the guest attempts to use fpu which hasn't been allowed
> + * by the root context.
> + */
> +static int _kvm_handle_fpu_disabled(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_run *run = vcpu->run;
> +
> +	/*
> +	 * If guest FPU not present, the FPU operation should have been
> +	 * treated as a reserved instruction!
> +	 * If FPU already in use, we shouldn't get this at all.
> +	 */
> +	if (WARN_ON(vcpu->arch.aux_inuse & KVM_LARCH_FPU)) {
> +		kvm_err("%s internal error\n", __func__);
> +		run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
> +		return RESUME_HOST;
> +	}
> +
> +	kvm_own_fpu(vcpu);
> +	return RESUME_GUEST;
> +}