Re: [PATCH v10 10/26] KVM: s390: interfaces to clear CRYCB masks

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 12 Sep 2018 15:43:00 -0400
Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:

> From: Tony Krowiak <akrowiak@linux.ibm.com>
> 
> Introduces two new KVM interface to clear the APM, AQM and ADM masks in
> the guest's CRYCB.  The VCPUs are taken out of SIE to ensure the VCPUs do
> not get out of sync.

Hm, that patch description does not quite match what the patch actually
does...

> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Acked-by: Halil Pasic <pasic@linux.ibm.com>
> Tested-by: Michael Mueller <mimu@linux.ibm.com>
> Tested-by: Farhan Ali <alifm@linux.ibm.com>
> Tested-by: Pierre Morel <pmorel@linux.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  arch/s390/include/asm/kvm_host.h |    2 ++
>  arch/s390/kvm/kvm-s390.c         |   15 +++++++++++++++
>  2 files changed, 17 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 423cce7..1e758fe 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -858,6 +858,8 @@ void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
>  void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
>  				 struct kvm_async_pf *work);
>  
> +void kvm_arch_crypto_clear_masks(struct kvm *kvm);
> +
>  extern int sie64a(struct kvm_s390_sie_block *, u64 *);
>  extern char sie_exit;
>  
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index d717041..ac4c93f 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2033,6 +2033,21 @@ static void kvm_s390_set_crycb_format(struct kvm *kvm)
>  		kvm->arch.crypto.crycbd |= CRYCB_FORMAT1;
>  }
>  
> +void kvm_arch_crypto_clear_masks(struct kvm *kvm)
> +{
> +	mutex_lock(&kvm->lock);
> +	kvm_s390_vcpu_block_all(kvm);
> +
> +	memset(&kvm->arch.crypto.crycb->apcb0, 0,
> +	       sizeof(kvm->arch.crypto.crycb->apcb0));
> +	memset(&kvm->arch.crypto.crycb->apcb1, 0,
> +	       sizeof(kvm->arch.crypto.crycb->apcb1));
> +
> +	kvm_s390_vcpu_unblock_all(kvm);
> +	mutex_unlock(&kvm->lock);
> +}
> +EXPORT_SYMBOL_GPL(kvm_arch_crypto_clear_masks);

...although this function looks fine.

> +
>  static u64 kvm_s390_get_initial_cpuid(void)
>  {
>  	struct cpuid cpuid;