Re: [PATCH v1 1/1] KVM: s390: pqap: fix AP status written to wrong half of GR1

[Christian Borntraeger <borntraeger@linux.ibm.com>]

Am 20.10.26 um 10:25 schrieb Gautam Gala:
> The AP Queue Status Word (APQSW) occupies bit positions 32-63 of GR1,
> i.e. the low 32 bits of the 64-bit register, while the upper 32 bits
> are reserved.
> 
> The no-hook fallback path in handle_pqap() synthesizes an APQSW and
> copies struct ap_queue_status directly into GPR1 using memcpy(). On
> big-endian s390 this places the APQSW in the upper 32 bits of the
> register rather than in the architecturally defined APQSW field.
> 
> Use union ap_queue_status_reg and assign its value directly to GPR1.
> This places APQSW in the correct half of the register and aligns the
> fallback path with the register layout used by the AP infrastructure.
> 
> Fixes: e5282de93105 ("s390: ap: kvm: add PQAP interception for AQIC")
> Reported-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> Signed-off-by: Gautam Gala <ggala@linux.ibm.com>

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>

Thanks. applied.

> ---
>   arch/s390/kvm/s390/priv.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/s390/kvm/s390/priv.c b/arch/s390/kvm/s390/priv.c
> index b3cb2c2c3aa7..ccb2a7830265 100644
> --- a/arch/s390/kvm/s390/priv.c
> +++ b/arch/s390/kvm/s390/priv.c
> @@ -592,7 +592,7 @@ EXPORT_SYMBOL_FOR_MODULES(kvm_s390_is_gpa_in_memslot, "vfio_ap");
>    */
>   static int handle_pqap(struct kvm_vcpu *vcpu)
>   {
> -	struct ap_queue_status status = {};
> +	union ap_queue_status_reg status = {};
>   	crypto_hook pqap_hook;
>   	unsigned long reg0;
>   	int ret;
> @@ -661,8 +661,8 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
>   	 * No hook means no driver to enable the SIE CRYCB and no queues.
>   	 * We send this response to the guest.
>   	 */
> -	status.response_code = 0x01;
> -	memcpy(&vcpu->run->s.regs.gprs[1], &status, sizeof(status));
> +	status.status.response_code = 0x01;
> +	vcpu->run->s.regs.gprs[1] = status.value;
>   	kvm_s390_set_psw_cc(vcpu, 3);
>   	return 0;
>   }