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| author | Nir Weiner <nir.weiner@oracle.com> | 2019-01-27 12:17:14 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-02-20 22:48:50 +0100 |
| commit | 7fa08e71b4a0591a518814fa78b32e124f90d587 (patch) | |
| tree | f8b66306b476c5b6e833bceef8a0434bc9116652 /virt | |
| parent | 8ab3c471eef20925bf64c6d4fa46e88cdb4e86d5 (diff) | |
| download | lwn-7fa08e71b4a0591a518814fa78b32e124f90d587.tar.gz lwn-7fa08e71b4a0591a518814fa78b32e124f90d587.zip | |
KVM: grow_halt_poll_ns() should never shrink vCPU halt_poll_ns
grow_halt_poll_ns() have a strange behavior in case
(halt_poll_ns_grow == 0) && (vcpu->halt_poll_ns != 0).
In this case, vcpu->halt_pol_ns will be set to zero.
That results in shrinking instead of growing.
Fix issue by changing grow_halt_poll_ns() to not modify
vcpu->halt_poll_ns in case halt_poll_ns_grow is zero
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Nir Weiner <nir.weiner@oracle.com>
Suggested-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index c9d0bc01f8cb..9c8a8bf6e686 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2188,8 +2188,11 @@ static void grow_halt_poll_ns(struct kvm_vcpu *vcpu) old = val = vcpu->halt_poll_ns; grow = READ_ONCE(halt_poll_ns_grow); + if (!grow) + goto out; + /* 10us base */ - if (val == 0 && grow) + if (val == 0) val = 10000; else val *= grow; @@ -2198,6 +2201,7 @@ static void grow_halt_poll_ns(struct kvm_vcpu *vcpu) val = halt_poll_ns; vcpu->halt_poll_ns = val; +out: trace_kvm_halt_poll_ns_grow(vcpu->vcpu_id, val, old); } |