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

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Message-Id: <ddb86d5e-35ef-daf2-c6b2-ad0869692c9a@linux.ibm.com>
Date:   Thu, 9 Aug 2018 10:57:20 +0200
From:   Pierre Morel <pmorel@...ux.ibm.com>
To:     David Hildenbrand <david@...hat.com>,
        Tony Krowiak <akrowiak@...ux.vnet.ibm.com>,
        linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     freude@...ibm.com, schwidefsky@...ibm.com,
        heiko.carstens@...ibm.com, borntraeger@...ibm.com,
        cohuck@...hat.com, kwankhede@...dia.com,
        bjsdjshi@...ux.vnet.ibm.com, pbonzini@...hat.com,
        alex.williamson@...hat.com, pmorel@...ux.vnet.ibm.com,
        alifm@...ux.vnet.ibm.com, mjrosato@...ux.vnet.ibm.com,
        jjherne@...ux.vnet.ibm.com, thuth@...hat.com,
        pasic@...ux.vnet.ibm.com, berrange@...hat.com,
        fiuczy@...ux.vnet.ibm.com, buendgen@...ibm.com,
        frankja@...ux.ibm.com
Subject: Re: [PATCH v8 19/22] KVM: s390: Clear Crypto Control Block when using
 vSIE

On 09/08/2018 10:10, David Hildenbrand wrote:
> On 08.08.2018 16:44, Tony Krowiak wrote:
>> From: Pierre Morel <pmorel@...ux.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@...ux.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

do you think I should squash this patch with the next one?

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

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