This is a note to let you know that I've just added the patch titled
KVM: s390: Optimize ucontrol path
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-s390-optimize-ucontrol-path.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2955c83f72801245afd0fe5c560cc75b82bea9aa Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Date: Thu, 6 Mar 2014 16:01:38 +0100
Subject: KVM: s390: Optimize ucontrol path
From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
commit 2955c83f72801245afd0fe5c560cc75b82bea9aa upstream.
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@xxxxxxxxxx>
Reviewed-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/kvm/kvm-s390.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -753,7 +753,8 @@ static int vcpu_post_run(struct kvm_vcpu
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);
}
Patches currently in stable-queue which might be from borntraeger@xxxxxxxxxx are
queue-3.14/kvm-s390-optimize-ucontrol-path.patch
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