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 <pmo...@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 <pmo...@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

right, thanks

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

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