Re: [PATCH v2 6/7] KVM: s390: Fix overclearing ESCA in case of error

[Janosch Frank <frankja@linux.ibm.com>]

On 7/13/26 17:08, Claudio Imbrenda wrote:
> If an attempt is made to create a vCPU with an already existing ID,
> the duplicated vCPU will be destroyed. When destroying a vCPU, its
> ESCA entry will be cleared. In the above scenario, the spurious
> duplicate vCPU is destroyed, but the ESCA entry corresponding to the
> original vCPU is cleared.
> 
> Fix by skipping clearing the ESCA entry if the vCPU creation was not
> successful, i.e. if the pointer to the ESCA in the state description is
> not set.
> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>   arch/s390/kvm/kvm-s390.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index fc0a884d7f54..6339a327a7be 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -3458,7 +3458,7 @@ static void sca_del_vcpu(struct kvm_vcpu *vcpu)
>   {
>   	struct esca_block *sca = vcpu->kvm->arch.sca;
>   
> -	if (!kvm_s390_use_sca_entries())
> +	if (!kvm_s390_use_sca_entries() || !vcpu->arch.sie_block->scaol)
>   		return;
>   
>   	clear_bit_inv(vcpu->vcpu_id, (unsigned long *)sca->mcn);


Oh boy.
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>