Re: [PATCH] KVM: Use thread debug register storage instead of kvm specific data

[Avi Kivity <avi@redhat.com>]

On 09/01/2009 02:16 PM, Avi Kivity wrote:
>
>>>           set_debugreg(0, 7);
>>>           set_debugreg(vcpu->arch.eff_db[0], 0);
>>>           set_debugreg(vcpu->arch.eff_db[1], 1);
>>> @@ -3645,15 +3638,14 @@ static int vcpu_enter_guest(struct kvm_vcpu 
>>> *vcpu)
>>>       trace_kvm_entry(vcpu->vcpu_id);
>>>       kvm_x86_ops->run(vcpu);
>>>
>>> -    if (unlikely(vcpu->arch.switch_db_regs)) {
>>> -        set_debugreg(0, 7);
>>> -        set_debugreg(vcpu->arch.host_db[0], 0);
>>> -        set_debugreg(vcpu->arch.host_db[1], 1);
>>> -        set_debugreg(vcpu->arch.host_db[2], 2);
>>> -        set_debugreg(vcpu->arch.host_db[3], 3);
>>> +    if (unlikely(vcpu->arch.switch_db_regs || 
>>> test_thread_flag(TIF_DEBUG))) {
>> IIRC, you must clear dr7 before loading dr0..3 to avoid spurious 
>> effects.
>
> Yeah, I thought of it but forgot to implement it.

Actually on the entry path it is done correctly, and on the exit path 
dr7 is cleared, so this patch is correct.

-- 
error compiling committee.c: too many arguments to function