KVM: x86: do not execute halted vcpus

Offline or uninitialized vcpu's can be executed if requested to perform
userspace work.

Follow Avi's suggestion to handle halted vcpu's in the main loop,
simplifying kvm_emulate_halt(). Introduce a new vcpu->requests bit to
indicate events that promote state from halted to running.

Also standardize vcpu wake sites.

Signed-off-by: Marcelo Tosatti <mtosatti <at> redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index de3b029f6adf..63e661be040a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -980,12 +980,12 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
         for (;;) {
                 prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE);
 
-                if (kvm_cpu_has_interrupt(vcpu))
-                        break;
-                if (kvm_cpu_has_pending_timer(vcpu))
-                        break;
-                if (kvm_arch_vcpu_runnable(vcpu))
+                if (kvm_cpu_has_interrupt(vcpu) ||
+                    kvm_cpu_has_pending_timer(vcpu) ||
+                    kvm_arch_vcpu_runnable(vcpu)) {
+                        set_bit(KVM_REQ_UNHALT, &vcpu->requests);
                         break;
+                }
                 if (signal_pending(current))
                         break;