Xen devel - Sep 2007 - get_callback_via for Windows PV drivers

Looking at the ''unmodified_drivers'', it appears that
I''m supposed to
tell the hypervisor the IRQ number to use to signal me. Under the
Windows DDK, I get an Interrupt Vector, which I don''t think is the same
as an IRQ number... and I think I''m supposed to work backwards from the
vector to try and figure out what IRQ I''m supposed to pass the
hypervisor.

If I right click on the PCI driver in ''Device Manager'', it
tells me that
the Xen PCI virtual device is using IRQ 28, is this the magic number
that I need to give to the hypervisor?

Thanks

James

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On 27/9/07 11:55, "James Harper" <james.harper@bendigoit.com.au>
wrote:
> Looking at the ''unmodified_drivers'', it appears that
I''m supposed to
> tell the hypervisor the IRQ number to use to signal me. Under the
> Windows DDK, I get an Interrupt Vector, which I don''t think is the
same
> as an IRQ number... and I think I''m supposed to work backwards
from the
> vector to try and figure out what IRQ I''m supposed to pass the
> hypervisor.
The documentation in public/hvm/params.h is pretty clear. Either you can
specify the PCI INTx line by bus,dev,fn,pin, or you can specify the GSI that
the line is ''wired'' to. Neither of these values is
determinable from the
interrupt vector. However, if you have probed the PCI device then you
probably know the (bus,dev,fn,pin) tuple, so you should probably aim to
specify that.

 -- Keir



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> On 27/9/07 11:55, "James Harper"
<james.harper@bendigoit.com.au>
wrote:
> 
> > Looking at the ''unmodified_drivers'', it appears that
I''m supposed to
> > tell the hypervisor the IRQ number to use to signal me. Under the
> > Windows DDK, I get an Interrupt Vector, which I don''t think
is the
same
> > as an IRQ number... and I think I''m supposed to work
backwards from
the
> > vector to try and figure out what IRQ I''m supposed to pass
the
> > hypervisor.
> 
> The documentation in public/hvm/params.h is pretty clear. Either you
can
> specify the PCI INTx line by bus,dev,fn,pin, or you can specify the
GSI
> that the line is ''wired'' to.
Unfortunately I''m not sure that I know what GSI actually means... I
believe it stands for Global System Interrupt, but I''m not sure that
that helps. Windows will give me the ''Translated'' interrupt,
which is
the vector, and the ''Raw'' interrupt, which is 28 in my case.
Could this
be the GSI?
> Neither of these values is determinable from the
> interrupt vector. However, if you have probed the PCI device then you
> probably know the (bus,dev,fn,pin) tuple, so you should probably aim
to
> specify that.
I can get bus, dev, and fn, but can''t seem to find
''pin'' from the
information that Windows gives me... if 28 isn''t the GSI, then
I''ll have
to look harder for this ''pin'' number in the windows
structures...

What is the simplest thing I could do to get the hypervisor to trigger
an interrupt? That would tell me for sure that it''s working. I have
only
implemented a tiny bit of the event channel logic, and no xen bus stuff
yet...

Thanks

James


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On 28/9/07 12:15, "James Harper" <james.harper@bendigoit.com.au>
wrote:
>> Neither of these values is determinable from the
>> interrupt vector. However, if you have probed the PCI device then you
>> probably know the (bus,dev,fn,pin) tuple, so you should probably aim
> to
>> specify that.
> 
> I can get bus, dev, and fn, but can''t seem to find
''pin'' from the
> information that Windows gives me... if 28 isn''t the GSI, then
I''ll have
> to look harder for this ''pin'' number in the windows
structures...
Read byte 0x3d in the PCI device config space. That returns the pin index.
> What is the simplest thing I could do to get the hypervisor to trigger
> an interrupt? That would tell me for sure that it''s working. I
have only
> implemented a tiny bit of the event channel logic, and no xen bus stuff
> yet...
Implement a simple console driver to talk to xenconsoled, perhaps?

 -- Keir



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> > I can get bus, dev, and fn, but can''t seem to find
''pin'' from the
> > information that Windows gives me... if 28 isn''t the GSI,
then I''ll
have
> > to look harder for this ''pin'' number in the windows
structures...
> 
> Read byte 0x3d in the PCI device config space. That returns the pin
index.

Using 28 as the irq appears to work - the ISR definitely get called by
xen (and locks up if I don''t do the right thing with the upcall_pending
flag).

Can you see a problem with doing it that way?

Thanks

James

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On 30/9/07 05:40, "James Harper" <james.harper@bendigoit.com.au>
wrote:
>>> I can get bus, dev, and fn, but can''t seem to find
''pin'' from the
>>> information that Windows gives me... if 28 isn''t the GSI,
then I''ll
> have
>>> to look harder for this ''pin'' number in the
windows structures...
>> 
>> Read byte 0x3d in the PCI device config space. That returns the pin
> index.
> 
> Using 28 as the irq appears to work - the ISR definitely get called by
> xen (and locks up if I don''t do the right thing with the
upcall_pending
> flag).
> 
> Can you see a problem with doing it that way?
No, since it sounds like that value is the GSI.

 -- Keir



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