KVM: set debug registers after "schedulable" section

The vcpu thread can be preempted after the guest_debug_pre() callback,
resulting in invalid debug registers on the new vcpu.

Move it inside the non-preemptable section.

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

1 files changed, 4 insertions, 5 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f1b0223c4088..4a033757a19e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3113,10 +3113,6 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         down_read(&vcpu->kvm->slots_lock);
         vapic_enter(vcpu);
 
-preempted:
-        if (vcpu->guest_debug.enabled)
-                kvm_x86_ops->guest_debug_pre(vcpu);
-
 again:
         if (vcpu->requests)
                 if (test_and_clear_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
@@ -3170,6 +3166,9 @@ again:
                 goto out;
         }
 
+        if (vcpu->guest_debug.enabled)
+                kvm_x86_ops->guest_debug_pre(vcpu);
+
         vcpu->guest_mode = 1;
         /*
          * Make sure that guest_mode assignment won't happen after
@@ -3244,7 +3243,7 @@ out:
         if (r > 0) {
                 kvm_resched(vcpu);
                 down_read(&vcpu->kvm->slots_lock);
-                goto preempted;
+                goto again;
         }
 
         post_kvm_run_save(vcpu, kvm_run);