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

[Pierre Morel]

On 09/08/2018 10:10, David Hildenbrand wrote:
> On 08.08.2018 16:44, Tony Krowiak wrote:
> > From: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxxx>
> > ---
> >   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
right, thanks

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

--
Pierre Morel
Linux/KVM/QEMU in BÃblingen - Germany