Re: [Qemu-devel] [PATCH 4/4] spapr: Add support for time base offset migration

[Alexey Kardashevskiy]

On 04/14/2014 04:37 PM, Alexander Graf wrote:
> 
> On 12.04.14 23:44, Benjamin Herrenschmidt wrote:
>> On Sat, 2014-04-12 at 16:31 +0200, Alexander Graf wrote:
>>> Don't we generate PHBs on the fly? How exactly is this going to help
>>> with the problem at hand?
>> We can still assign the interrupts as a fixed function of the PHB
>> number...
> 
> Yes, but we create those depending on the order with which -device gets
> called IIUC. That's really what the underlying issue is. If we had 500
> prepopulated PHBs that PCI devices get assigned to we wouldn't have the
> problem (but different ones thanks to massive waste of memory and other
> resources).
> 
> So we either have to create some way to make interrupt numbering a function
> of something very simple we plug the PHB into, like a virtual pseries slot
> number which we multiply by x to get an irq number range. Or we'd have to
> manually link up PHB IRQ lines to XICS IRQ lines on the command line.


Our additional PHBs require @index property which is used to calculate base
MMIO and IO ranges. That we could use for LSI/MSI too.



-- 
Alexey