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* 3.19-rc4: Xen pci-passthrough regression, bisected to commit cffe0a2b5a34c95a4dadc9ec7132690a5b0f6687 "x86, irq: Keep balance of IOAPIC pin reference count"
@ 2015-01-14 14:15 Sander Eikelenboom
  2015-01-14 14:58 ` David Vrabel
  0 siblings, 1 reply; 4+ messages in thread
From: Sander Eikelenboom @ 2015-01-14 14:15 UTC (permalink / raw)
  To: David Vrabel, Jiang Liu, Konrad Rzeszutek Wilk; +Cc: xen-devel, linux-kernel

Hi Gerry / David / Konrad,

Some more testing uncovered another issue under Xen, this time with PCI-passthrough.

I have bisected it to the following commit: 
cffe0a2b5a34c95a4dadc9ec7132690a5b0f6687 "x86, irq: Keep balance of IOAPIC pin reference count"

It causes these symptoms:

- On Intel
  - Running on Xen with pci devices seized on host boot with xen-pciback.hide= parameter
  - Running a HVM guest with PCI passthrough of two devices (NIC + wireless NIC)
  - While the driver loads fine, the device isn't working properly, looking in /proc/interrupts in the guest
    shows that it doesn't receive any interrupts.
  - Reverting this particular commit (in the dom0 kernel only) makes the device receive interrupts and work properly again.

- On AMD (more subtle symptom) 
  - Running on Xen with pci devices seized on host boot with xen-pciback.hide= parameter
  - Running a HVM guest with PCI passthrough of one devices (videograbber)
  - While the driver loads fine and the device looks like it's working, the videostream isn't stable and it skips or repeats frames.
  - Reverting this particular commit (in the dom0 kernel only) makes the device work properly again with a stable videostream.

--
Sander


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2015-01-15 11:20 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-01-14 14:15 3.19-rc4: Xen pci-passthrough regression, bisected to commit cffe0a2b5a34c95a4dadc9ec7132690a5b0f6687 "x86, irq: Keep balance of IOAPIC pin reference count" Sander Eikelenboom
2015-01-14 14:58 ` David Vrabel
2015-01-14 16:17   ` Sander Eikelenboom
2015-01-15 11:20     ` Jiang Liu

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