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

Halil Pasic
2018-09-24T11:50:36Z

On 09/24/2018 01:01 PM, Cornelia Huck wrote:
> 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...
>

You mean it is not obvious where the masks get cleared? Well the APCB is
defined to contain exactly the three masks. As far as I can tell the patch
description is correct.

Regards,
Halil

>>
>> 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;
>