Re: Remaining passthrough/VT-d tasks list

[Avi Kivity <avi@redhat.com>]

Yang, Sheng wrote:
>> We only have three pci interrupts at this point (though this could be
>> easily extended); if you start the guest with a non-trivial number of
>> devices, you will have shared guest interrupts.
>>
>> (of course, when I pointed this out during review, people said it could
>> be done later, then forgot all about it)
>>
>>     
> ..... 
>
> I think it's a performance issue, not break it? How about do it like Xen side? 
> Try best to avoid the share, extended the pci interrupts, improve hash 
> algorithm. Is there anything else we can do?
>   


Two separate issues:

1. only three guest pci interrupts

That's a performance issue, not correctness.  can be fixed by using gsi 
16-23 in APIC mode, and by adding another IOAPIC (so we can use gsi 
16-47).  Anthony Xu posted some patches for this, not sure where this 
stands, but it was the right approach.

2. shared guest pci interrupts

That's a correctness issue.  No matter how many interrupts we have, we 
may have sharing issues.  Of course with only three the issue is very 
pressing since we will get sharing with just a few devices.  Currently 
if two assigned devices share a guest interrupts, or if an emulated 
device shares an interrupt with an assigned device, things will break.

They need to be fixed independently.

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