[ Upstream commit
7cae2bedcbd4680b155999655e49c27b9cf020fa ]
As reported at https://bugs.launchpad.net/qemu/+bug/1494350,
it is possible to have vcpu->arch.st.last_steal initialized
from a thread other than vcpu thread, say the iothread, via
KVM_SET_MSRS.
Which can cause an overflow later (when subtracting from vcpu threads
sched_info.run_delay).
To avoid that, move steal time accumulation to vcpu entry time,
before copying steal time data to guest.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
static void record_steal_time(struct kvm_vcpu *vcpu)
{
+ accumulate_steal_time(vcpu);
+
if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
return;
if (!(data & KVM_MSR_ENABLED))
break;
- vcpu->arch.st.last_steal = current->sched_info.run_delay;
-
- preempt_disable();
- accumulate_steal_time(vcpu);
- preempt_enable();
-
kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
break;
vcpu->cpu = cpu;
}
- accumulate_steal_time(vcpu);
kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
}