[PATCH] RE: [Xen-ia64-devel] xencons interrupt problem

[Alex Williamson <alex.williamson@xxxxxx>]

On Mon, 2006-06-26 at 11:27 +0800, Tian, Kevin wrote:
> I seem to understand your proposal now. Do you mean that some early 
> table will report the irq line information for the console device out of the 
> ACPI table? If that's the case, I think changes required to achieve this 
> purpose is:
>       1. Modify assign_irq_vector hypercall to allow passing into GSI for 
> check sharing with PCI serial
>               If it's sharing, return existing vector instead of a new 
> allocation
>       2. Add a new flag to indicate such sharing between xen and dom0, 
> and remove checks against this style in all places.
>               When assertion on this irq line happens, pass to xen first and 
> then to dom0
>       3. Do we need to hide such console from dom0, since the latter 
> only uses para-virtualized xenconsole?
> 
> En... above should be enough if I understand your requirement correctly.


   I have something working, please tell me what you think.  Modifying
assign_irq_vector() to pass in a GSI seemed rather intrusive to the
guest, so I took a different approach.  Instead I recognize the guest
trying to overwrite a Xen owned vector, store the guest vector in an
array and set it up as a "Xen redirect" vector.  These vectors are
serviced from __do_IRQ after the Xen handler.  There is only one
redirect vector allowed per Xen vector, but that seems sufficient at
this point.  This allows full use of both the PCI UART (owned by Xen)
and the PCI NIC (owned by the guest) sharing a physical RTE.  Let me
know if you think this approach is acceptable.  Thanks,

        Alex

Signed-off-by: Alex Williamson <alex.williamson@xxxxxx>

Attachment: xen_irq_redirect.patch
Description: Text Data

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