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

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

On Wednesday 18 February 2009 20:36:10 Avi Kivity wrote:
> Sheng Yang wrote:
> >>>   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...
>
> Which bitmap?  I'm confused.
>
> I'm talking about unifying the existing array
> (assigned_dev->host_msix_entries[]) with ->host_irq.  Also since we need
> an array for INTx when a function uses INT[BCD].
>
> So we'll have assigned_dev->host_irqs[], each entry can be INTx or MSI
> or MSIx.
>
> > OK. I think array is reasonable, but the length is a problem, as I did
> > before. How long would you like?
>
> MAX(4, KVM_MAX_MSIX_ENTRIES), no?

Oh, yeah, I misunderstood it(wrong context)...

Need more adjustment on the type, for host_msix_entries is used with 
pci_enable_msix. So I'd like to put it a bit later.

-- 
regards
Yang, Sheng