Re: [PATCH] KVM: x86: don't hold kvm->lock in KVM_SET_GSI_ROUTING

[David Hildenbrand <david@xxxxxxxxxx>]

On 26.04.2017 16:27, Radim Krčmář wrote:
> 2017-04-26 10:40+0200, David Hildenbrand:
>> On 25.04.2017 21:59, Radim Krčmář wrote:
>>> 2017-04-25 21:03+0200, David Hildenbrand:
>>>> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
>>>> @@ -504,6 +504,7 @@ void vcpu_put(struct kvm_vcpu *vcpu);
>>>>  #ifdef __KVM_HAVE_IOAPIC
>>>>  void kvm_arch_post_irq_ack_notifier_list_update(struct kvm *kvm);
>>>>  void kvm_arch_post_irq_routing_update(struct kvm *kvm);
>>>> +bool kvm_arch_can_set_irq_routing(struct kvm *kvm);
>>>
>>> (A nitpick: it might be useful even without __KVM_HAVE_IOAPIC so weak
>>>  linking would probably be cleaner for a slow path.)
>>>
>>>>  #else
>>>>  static inline void kvm_arch_post_irq_ack_notifier_list_update(struct kvm *kvm)
>>>>  {
>>>> @@ -511,6 +512,10 @@ static inline void kvm_arch_post_irq_ack_notifier_list_update(struct kvm *kvm)
>>>>  static inline void kvm_arch_post_irq_routing_update(struct kvm *kvm)
>>>>  {
>>>>  }
>>>> +static bool kvm_arch_can_set_irq_routing(struct kvm *kvm)
>>>> +{
>>>> +	return true;
>>>> +}
>>>>  #endif
>>>>  
>>
>> Makes sense, shall I resend or can you fix that up when applying?
> 
> Please send a v2, it's going to be automatically compile-tested on all
> arches that way. :)
> 

Using a weak symbol for the first time... Is the following what you had in mind?

---- snip ----
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 397b7b5..b725d4e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1009,6 +1009,7 @@ static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq)
 #define KVM_MAX_IRQ_ROUTES 1024
 #endif
 
+bool kvm_arch_can_set_irq_routing(struct kvm *kvm);
 int kvm_set_irq_routing(struct kvm *kvm,
                        const struct kvm_irq_routing_entry *entries,
                        unsigned nr,
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index cc30d01..a080659 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -172,6 +172,11 @@ void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
 {
 }
 
+bool __attribute__((weak)) kvm_arch_can_set_irq_routing(struct kvm *kvm)
+{
+       return true;
+}
+
 int kvm_set_irq_routing(struct kvm *kvm,
                        const struct kvm_irq_routing_entry *ue,
                        unsigned nr,
---- snip ----

-- 

Thanks,

David