KVM: set debug registers after "schedulable" section

(cherry picked from commit 29415c37f043d1d54dcf356601d738ff6633b72b)

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5911677d1d7b37ee5b89b06ad0088dadcad424c8..1454992e6ace17d8d194448748bd1f4258749f71 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2839,10 +2839,6 @@ 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))
@@ -2896,6 +2892,9 @@ 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
@@ -2970,7 +2969,7 @@ out:
        if (r > 0) {
                kvm_resched(vcpu);
                down_read(&vcpu->kvm->slots_lock);
-               goto preempted;
+               goto again;
        }
 
        post_kvm_run_save(vcpu, kvm_run);