[PATCH 1/2] KVM: arm64: Fix enforcement of upper bound on MDCR_EL2.HPMN

[Zenghui Yu]

On 2025/7/3 21:57, Ben Horgan wrote:
> Previously, u64_replace_bits() was used to no effect as the return value
> was ignored. Convert to u64p_replace_bits() so the value is updated in
> place.
> 
> Signed-off-by: Ben Horgan <ben.horgan at arm.com>
> Fixes: efff9dd2fee7 ("KVM: arm64: Handle out-of-bound write to MDCR_EL2.HPMN")
> Cc: Marc Zyngier <maz at kernel.org>
> Cc: stable at vger.kernel.org
> ---
>  arch/arm64/kvm/sys_regs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 76c2f0da821f..c20bd6f21e60 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -2624,7 +2624,7 @@ static bool access_mdcr(struct kvm_vcpu *vcpu,
>  	 */
>  	if (hpmn > vcpu->kvm->arch.nr_pmu_counters) {
>  		hpmn = vcpu->kvm->arch.nr_pmu_counters;
> -		u64_replace_bits(val, hpmn, MDCR_EL2_HPMN);
> +		u64p_replace_bits(&val, hpmn, MDCR_EL2_HPMN);
>  	}
>  
>  	__vcpu_assign_sys_reg(vcpu, MDCR_EL2, val);

Reviewed-by: Zenghui Yu <yuzenghui at huawei.com>

Thanks!