Re: [PATCH v8 19/22] KVM: s390: Clear Crypto Control Block when using vSIE

David Hildenbrand
2018-08-09T08:10:45Z

On 08.08.2018 16:44, Tony Krowiak wrote:
> From: Pierre Morel <pmorel@linux.ibm.com>
>
> When we clear the Crypto Control Block (CRYCB) used by a guest
> level 2, the vSIE shadow CRYCB for guest level 3 must be updated
> before the guest uses it.
>
> We achieve this by using the KVM_REQ_VSIE_RESTART synchronous
> request for each vCPU belonging to the guest to force the reload
> of the shadow CRYCB before rerunning the guest level 3.
>
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
> arch/s390/kvm/kvm-s390.c | 7 +++++++
> 1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 0d03249..9203f0b 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -1921,6 +1921,9 @@ static void kvm_s390_set_crycb_format(struct kvm *kvm)
>
> void kvm_arch_crypto_clear_masks(struct kvm *kvm)
> {
> + int i;
> + struct kvm_vcpu *vcpu;
> +
> mutex_lock(&kvm->lock);
> kvm_s390_vcpu_block_all(kvm);
>
> @@ -1929,6 +1932,10 @@ void kvm_arch_crypto_clear_masks(struct kvm *kvm)
> memset(&kvm->arch.crypto.crycb->apcb1, 0,
> sizeof(kvm->arch.crypto.crycb->apcb1));
>
> + /* recreate the shadow crycb for each vcpu */
> + kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_s390_sync_request(KVM_REQ_VSIE_RESTART, vcpu);

We have kvm_s390_sync_request_broadcast(), which should boil down to a
one-liner

> +
> kvm_s390_vcpu_unblock_all(kvm);
> mutex_unlock(&kvm->lock);
> }
>

--

Thanks,

David / dhildenb