lkml.org 
[lkml]   [2014]   [May]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.14 033/158] KVM: s390: Optimize ucontrol path
    Date
    3.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Christian Borntraeger <borntraeger@de.ibm.com>

    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@de.ibm.com>
    Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    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);
    }



    \
     
     \ /
      Last update: 2014-05-04 19:41    [W:4.153 / U:0.152 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site