linux-kernel - Re: [PATCH v1 1/2] KVM: s390: Tracing APCB changes

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Date:   Fri, 5 Oct 2018 10:49:25 +0200
From:   Cornelia Huck <cohuck@...hat.com>
To:     Pierre Morel <pmorel@...ux.ibm.com>
Cc:     borntraeger@...ibm.com, david@...hat.com,
        linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org,
        kvm@...r.kernel.org, frankja@...ux.ibm.com, akrowiak@...ux.ibm.com,
        pasic@...ux.ibm.com
Subject: Re: [PATCH v1 1/2] KVM: s390: Tracing APCB changes

On Fri,  5 Oct 2018 10:31:09 +0200
Pierre Morel <pmorel@...ux.ibm.com> wrote:

> kvm_arch_crypto_set_masks is a new function to centralize
> the setup the APCB masks inside the CRYCB SIE satelite.

s/satelite/satellite/

> 
> To trace APCB mask changes, we add KVM_EVENT() tracing to
> both kvm_arch_crypto_set_masks and kvm_arch_crypto_clear_masks.
> 
> Signed-off-by: Pierre Morel <pmorel@...ux.ibm.com>
> ---
>  arch/s390/include/asm/kvm_host.h |  2 ++
>  arch/s390/kvm/kvm-s390.c         | 41 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 36d3531..22aa4da 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -861,6 +861,8 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
>  				 struct kvm_async_pf *work);
>  
>  void kvm_arch_crypto_clear_masks(struct kvm *kvm);
> +void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
> +			       unsigned long *aqm, unsigned long *adm);
>  
>  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 d3ea721..e871e5a 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2057,6 +2057,46 @@ static void kvm_s390_set_crycb_format(struct kvm *kvm)
>  		kvm->arch.crypto.crycbd |= CRYCB_FORMAT1;
>  }
>  
> +void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
> +			       unsigned long *aqm, unsigned long *adm)
> +{
> +	struct kvm_s390_crypto_cb *crycb = kvm->arch.crypto.crycb;
> +
> +	mutex_lock(&kvm->lock);
> +	kvm_s390_vcpu_block_all(kvm);
> +
> +	switch (kvm->arch.crypto.crycbd & CRYCB_FORMAT_MASK) {
> +	case CRYCB_FORMAT2: /* APCB1 use 256 bits */
> +		memcpy(crycb->apcb1.apm, apm, 32);
> +		VM_EVENT(kvm, 3, "SET CRYCB: apm %016lx %016lx %016lx %016lx",
> +			 apm[0], apm[1], apm[2], apm[3]);
> +		memcpy(crycb->apcb1.aqm, aqm, 32);
> +		VM_EVENT(kvm, 3, "SET CRYCB: aqm %016lx %016lx %016lx %016lx",
> +			 aqm[0], aqm[1], aqm[2], aqm[3]);
> +		memcpy(crycb->apcb1.adm, adm, 32);
> +		VM_EVENT(kvm, 3, "SET CRYCB: adm %016lx %016lx %016lx %016lx",
> +			 adm[0], adm[1], adm[2], adm[3]);
> +		break;
> +	case CRYCB_FORMAT1:
> +	case CRYCB_FORMAT0: /* Fall through both use APCB0 */
> +		memcpy(crycb->apcb0.apm, apm, 8);
> +		memcpy(crycb->apcb0.aqm, aqm, 2);
> +		memcpy(crycb->apcb0.adm, adm, 2);
> +		VM_EVENT(kvm, 3, "SET CRYCB: apm %016lx aqm %04x adm %04x",
> +			 apm[0], *((unsigned short *)aqm),
> +			 *((unsigned short *)adm));
> +		break;
> +	default:	/* Can not happen */
> +		break;
> +	}
> +
> +	/* recreate the shadow crycb for each vcpu */
> +	kvm_s390_sync_request_broadcast(kvm, KVM_REQ_VSIE_RESTART);
> +	kvm_s390_vcpu_unblock_all(kvm);
> +	mutex_unlock(&kvm->lock);


The locking and requests makes me wonder if we missed them before...
were they simply not needed for the prior use case (mdev group
notifier)?

> +}
> +EXPORT_SYMBOL_GPL(kvm_arch_crypto_set_masks);
> +
>  void kvm_arch_crypto_clear_masks(struct kvm *kvm)
>  {
>  	mutex_lock(&kvm->lock);
> @@ -2067,6 +2107,7 @@ void kvm_arch_crypto_clear_masks(struct kvm *kvm)
>  	memset(&kvm->arch.crypto.crycb->apcb1, 0,
>  	       sizeof(kvm->arch.crypto.crycb->apcb1));
>  
> +	VM_EVENT(kvm, 3, "%s", "CLR CRYCB:");
>  	/* recreate the shadow crycb for each vcpu */
>  	kvm_s390_sync_request_broadcast(kvm, KVM_REQ_VSIE_RESTART);
>  	kvm_s390_vcpu_unblock_all(kvm);