Re: [PATCH 3/3] KVM: Enable MSI-X for KVM assigned device

[Sheng Yang <sheng@linux.intel.com>]

On Wed, Feb 18, 2009 at 10:45:19AM +0000, Avi Kivity wrote:
> Sheng Yang wrote:
>> index a2dfbe0..78480d0 100644
>> --- a/include/linux/kvm.h
>> +++ b/include/linux/kvm.h
>> @@ -440,6 +440,9 @@ struct kvm_irq_routing {
>>  };
>>   #endif
>> +#if defined(CONFIG_X86)
>> +#define KVM_CAP_DEVICE_MSIX 26
>> +#endif
>>   
>
> We switched to a different way of depending on CONFIG_X86, see the other  
> KVM_CAP defines.

Thanks to point it out. :)

>
>>   struct kvm_assigned_msix_nr {
>>  	__u32 assigned_dev_id;
>>  	__u16 entry_nr;
>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>> index 4010802..d3acb37 100644
>> --- a/virt/kvm/kvm_main.c
>> +++ b/virt/kvm/kvm_main.c
>> @@ -280,13 +280,33 @@ static void kvm_free_assigned_irq(struct kvm *kvm,
>>  	 * now, the kvm state is still legal for probably we also have to wait
>>  	 * interrupt_work done.
>>  	 */
>> -	disable_irq_nosync(assigned_dev->host_irq);
>> -	cancel_work_sync(&assigned_dev->interrupt_work);
>> +	if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_MSIX) {
>> +		int i;
>> +		for (i = 0; i < assigned_dev->entries_nr; i++)
>> +			disable_irq_nosync(assigned_dev->
>> +					   host_msix_entries[i].vector);
>> +
>> +		cancel_work_sync(&assigned_dev->interrupt_work);
>> +
>> +		for (i = 0; i < assigned_dev->entries_nr; i++)
>> +			free_irq(assigned_dev->host_msix_entries[i].vector,
>> +				 (void *)assigned_dev);
>> +
>> +		assigned_dev->entries_nr = 0;
>> +		kfree(assigned_dev->host_msix_entries);
>> +		kfree(assigned_dev->guest_msix_entries);
>> +		pci_disable_msix(assigned_dev->dev);
>> +	} else {
>> +		/* Deal with MSI and INTx */
>> +		disable_irq_nosync(assigned_dev->host_irq);
>> +		cancel_work_sync(&assigned_dev->interrupt_work);
>>   
>
> How about always have an array?  That will also allow us to deal with  
> INTx where x=B,C,D.
>
> Currently for MSI and INTx the array will hold just one active element.

So array, or bitmap? I remember I changed it to bitmap accounding to your
first comment...

OK. I think array is reasonable, but the length is a problem, as I did before. How long would you like?

-- 
regards
Yang, Sheng