Re: [PATCH v1] KVM: s390: GISA: sort out physical vs virtual pointers usage

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Mon,  7 Nov 2022 09:57:27 +0100
Nico Boehr <nrb@linux.ibm.com> wrote:

> Fix virtual vs physical address confusion (which currently are the same).
> 
> In chsc_sgib(), do the virtual-physical conversion in the caller since
> the caller needs to make sure it is a 31-bit address and zero has a
> special meaning (disassociating the GIB).
> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

> ---
>  arch/s390/kvm/interrupt.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
> index ab569faf0df2..ae018217eac8 100644
> --- a/arch/s390/kvm/interrupt.c
> +++ b/arch/s390/kvm/interrupt.c
> @@ -3104,9 +3104,9 @@ static enum hrtimer_restart gisa_vcpu_kicker(struct hrtimer *timer)
>  static void process_gib_alert_list(void)
>  {
>  	struct kvm_s390_gisa_interrupt *gi;
> +	u32 final, gisa_phys, origin = 0UL;
>  	struct kvm_s390_gisa *gisa;
>  	struct kvm *kvm;
> -	u32 final, origin = 0UL;
>  
>  	do {
>  		/*
> @@ -3132,9 +3132,10 @@ static void process_gib_alert_list(void)
>  		 * interruptions asap.
>  		 */
>  		while (origin & GISA_ADDR_MASK) {
> -			gisa = (struct kvm_s390_gisa *)(u64)origin;
> +			gisa_phys = origin;
> +			gisa = phys_to_virt(gisa_phys);
>  			origin = gisa->next_alert;
> -			gisa->next_alert = (u32)(u64)gisa;
> +			gisa->next_alert = gisa_phys;
>  			kvm = container_of(gisa, struct sie_page2, gisa)->kvm;
>  			gi = &kvm->arch.gisa_int;
>  			if (hrtimer_active(&gi->timer))
> @@ -3418,6 +3419,7 @@ void kvm_s390_gib_destroy(void)
>  
>  int kvm_s390_gib_init(u8 nisc)
>  {
> +	u32 gib_origin;
>  	int rc = 0;
>  
>  	if (!css_general_characteristics.aiv) {
> @@ -3439,7 +3441,8 @@ int kvm_s390_gib_init(u8 nisc)
>  	}
>  
>  	gib->nisc = nisc;
> -	if (chsc_sgib((u32)(u64)gib)) {
> +	gib_origin = virt_to_phys(gib);
> +	if (chsc_sgib(gib_origin)) {
>  		pr_err("Associating the GIB with the AIV facility failed\n");
>  		free_page((unsigned long)gib);
>  		gib = NULL;