Re: [PATCH v2] KVM: PPC: Book3S HV: Refactor HFSCR emulation for KVM guests

[Madhavan Srinivasan <maddy@linux.ibm.com>]

On 7/16/24 5:22 PM, Gautam Menghani wrote:
> Refactor HFSCR emulation for KVM guests when they exit out with
> H_FAC_UNAVAIL to use a switch case instead of checking all "cause"
> values, since the "cause" values are mutually exclusive; and this is
> better expressed with a switch case.
>
> Signed-off-by: Gautam Menghani <gautam@linux.ibm.com>
> ---
> V1 -> V2:
> 1. Reword changelog to point out mutual exclusivity of HFSCR bits.
> 2. Reword commit message to match other commits in book3s_hv.c


Minor: I guess you mean "Reword the subject line"

Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com>



>
>   arch/powerpc/kvm/book3s_hv.c | 16 ++++++++++++----
>   1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index daaf7faf21a5..50797b0611a2 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -1922,14 +1922,22 @@ static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu,
>   
>   		r = EMULATE_FAIL;
>   		if (cpu_has_feature(CPU_FTR_ARCH_300)) {
> -			if (cause == FSCR_MSGP_LG)
> +			switch (cause) {
> +			case FSCR_MSGP_LG:
>   				r = kvmppc_emulate_doorbell_instr(vcpu);
> -			if (cause == FSCR_PM_LG)
> +				break;
> +			case FSCR_PM_LG:
>   				r = kvmppc_pmu_unavailable(vcpu);
> -			if (cause == FSCR_EBB_LG)
> +				break;
> +			case FSCR_EBB_LG:
>   				r = kvmppc_ebb_unavailable(vcpu);
> -			if (cause == FSCR_TM_LG)
> +				break;
> +			case FSCR_TM_LG:
>   				r = kvmppc_tm_unavailable(vcpu);
> +				break;
> +			default:
> +				break;
> +			}
>   		}
>   		if (r == EMULATE_FAIL) {
>   			kvmppc_core_queue_program(vcpu, SRR1_PROGILL |