Re: [v1] KVM: s390: VSIE: sort out virtual/physical address in pin_guest_page

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

Am 24.10.22 um 18:02 schrieb Nico Boehr:
> pin_guest_page() used page_to_virt() to calculate the hpa of the pinned
> page. This currently works, because virtual and physical addresses are
> the same. Use page_to_phys() instead to resolve the virtual-real address
> confusion.
> 
> One caller of pin_guest_page() actually expected the hpa to be a hva, so
> add the missing phys_to_virt() conversion here.
> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
> ---
>   arch/s390/kvm/vsie.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
> index 94138f8f0c1c..c6a10ff46d58 100644
> --- a/arch/s390/kvm/vsie.c
> +++ b/arch/s390/kvm/vsie.c
> @@ -654,7 +654,7 @@ static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa)
>   	page = gfn_to_page(kvm, gpa_to_gfn(gpa));
>   	if (is_error_page(page))
>   		return -EINVAL;
> -	*hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK);
> +	*hpa = (hpa_t)page_to_phys(page) + (gpa & ~PAGE_MASK);
>   	return 0;
>   }
>   
> @@ -869,7 +869,7 @@ static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
>   		WARN_ON_ONCE(rc);
>   		return 1;
>   	}
> -	vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa;
> +	vsie_page->scb_o = (struct kvm_s390_sie_block *)phys_to_virt(hpa);

Do we still need the cast here? phys_to_virt should return a void * and the assignment should succeed.


>   	return 0;
>   }
>