Re: [Xen-devel] pci-passthrough loses msi-x interrupts ability after domain destroy

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.09.17 at 21:50, <jerome.oufella@xxxxxxxxxxxxxxxxxxxx> wrote:
> - On Dom0, 'lspci -vv' on that PCIe device between the "working" and 
> the "muted interrupts" states, I noted a difference between the 
> MSI-X caps: 
> 
> - Capabilities: [70] MSI-X: Enable- Count=5 Masked- <-- IRQs will work if 
> domain started 
> + Capabilities: [70] MSI-X: Enable- Count=5 Masked+ <-- IRQs won't work if 
> domain started
>                                             ^^^^^^^

And did you verify that the OS actually makes an attempt to clear
this mask-all flag? If such an attempt doesn't have the intended
effect, finding the problem location in the code and sending a
fix can't be that difficult. If otoh the guest doesn't do this, then
we'd need to figure out whether we leave the device in a wrong
state after de-assigning it from the original guest instance (albeit,
as Roger said, the reset the device is supposed to go through
would be expected to clear it). I can certainly see an OS not
necessarily expecting the bit to be set when first gaining control
of the device. For this, look at the lspci output for the device in
Dom0 between shutting down and then restarting the guest.

Jan


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