[Qemu-devel] Windows doesn't like MSI/MSI-X

[Hannes Reinecke <hare@suse.de>]

Hi all,

recently I've tried to teach megasas MSI/MSI-X. While it works 
perfectly under Linux, Windows refuses to.

With really strange symptoms:
Windows Vista will BSOD when both MSI/MSI-X registers are present, 
and Windows 7 will hang as Windows (apparently) thinks MSI/MSI-X is 
enabled, whereas qemu doesn't and uses INTx.
So the Windows 7 guest will never see any interrupts.

The _really_ odd thing is that when I remove the MSI-X capability 
Windows will fall back to INTx and everything works.

Even more curious is that from the logs Windows will only ever write 
zeros into the MSI/MSI-X config registers.
Which makes me wonder what's going on there.

As I'm not sure if that's my fault I was wondering if anybody every 
succeeded in getting AHCI to use MSI under Windows.
Any pointers?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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