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KVM: s390: Optimize ucontrol path

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Since commit 7c470539c95630c1f2a10f109e96f249730b75eb
(s390/kvm: avoid automatic sie reentry) we will run through the C code
of KVM on host interrupts instead of just reentering the guest. This
will result in additional ucontrol exits (at least HZ per second). Let
handle a 0 intercept in the kernel and dont return to userspace,
even if in ucontrol mode.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
CC: stable@vger.kernel.org
This commit is contained in:
Christian Borntraeger 2014-03-06 16:01:38 +01:00
parent fed495d25e
commit 2955c83f72
1 changed files with 2 additions and 1 deletions
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3
arch/s390/kvm/kvm-s390.c
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@ -896,7 +896,8 @@ static int vcpu_post_run(struct kvm_vcpu *vcpu, int exit_reason)
if (rc == 0) {
if (kvm_is_ucontrol(vcpu->kvm))
rc = -EOPNOTSUPP;
/* Don't exit for host interrupts. */
rc = vcpu->arch.sie_block->icptcode ? -EOPNOTSUPP : 0;
else
rc = kvm_handle_sie_intercept(vcpu);
}