[Xen-devel] [RFC][PATCH 4/6] HVM PCI Passthrough (non-IOMMU)

["Guy Zana" <guy@xxxxxxxxxxxx>]

int.patch:

    - Supports only level-triggered interrupts. Edge interrupts support
will be 
      added shortly (should be fairly simple)
    - Change polarity trick: in order to reflect the external device's
assertion
      state, the ioapic pin gets its polarity changed whenever an
interrupt
      occur. So an interrupt is generated when the _external_ line is
asserted 
      (then, polarity change is done) and another interrupt when the
_external_ 
      line is deassered (as a result from the polarity change), this
continues 
      repeatedly. 
    - It is implemented by introducing a new hw_interrupt_type, which is
exactly 
      the same as the ioapic_level_type hw_interrupt_type with its end()

      callback replaced (see io_apic.c for more details).
    - State machine:
      Whenever an interrupt occur (both for an assertion or
deassertion):
          1. Ack & Mask the interrupt
          2. Assert/Deassert virtual line of NativeDom (Interrupt
action).
          3. Change pin's polarity
          4. EOI & Unmask

Signed-off-by: Guy Zana <guy@xxxxxxxxxxxx>

Attachment: int.patch
Description: int.patch

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