Re: [PATCH 1/2] KVM: provide irq_unsafe kvm_guest_{enter|exit}

Christian Borntraeger
2015-04-30T11:59:13Z

Am 30.04.2015 um 14:02 schrieb Christian Borntraeger:
> Am 30.04.2015 um 14:01 schrieb Christian Borntraeger:
>> Am 30.04.2015 um 13:50 schrieb Paolo Bonzini:
>>>
>>>
>>> On 30/04/2015 13:43, Christian Borntraeger wrote:
>>>> +/* must be called with irqs disabled */
>>>> +static inline void __kvm_guest_enter(void)
>>>> {
>>>> - unsigned long flags;
>>>> -
>>>> - BUG_ON(preemptible());
>>>
>>> Please keep the BUG_ON() in kvm_guest_enter. Otherwise looks good, thanks!
>
> Ah, you mean have the BUG_ON in the non underscore version? Yes, makes sense.

Hmmm, too quick.
the BUG_ON was there to make sure that rcu_virt_note_context_switch is safe.
The reworked code pulls the rcu_virt_note_context_switch within the irq_save
section so we no longer need this BUG_ON, no?

Christian