[PATCH] KVM: fix polling for guest halt continued even if disable it

From: Wanpeng Li
Date: Mon Sep 14 2015 - 05:39:10 EST


If there is already some polling ongoing, it's impossible to disable the
polling, since as soon as somebody sets halt_poll_ns to 0, polling will
never stop, as grow and shrink are only handled if halt_poll_ns is != 0.

This patch fix it by reset vcpu->halt_poll_ns in order to stop polling
when polling is disabled.

Reported-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
---
virt/kvm/kvm_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4662a88..f756cac0 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2012,7 +2012,8 @@ out:
else if (vcpu->halt_poll_ns < halt_poll_ns &&
block_ns < halt_poll_ns)
grow_halt_poll_ns(vcpu);
- }
+ } else
+ vcpu->halt_poll_ns = 0;

trace_kvm_vcpu_wakeup(block_ns, waited);
}
--
1.9.1

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