[Qemu-devel] [PATCH 0/3] apic: Implement handling for MSI redirection hint in IRQ delivery

[James Sullivan <sullivan.james.f@gmail.com>]

This set of patches implements handling for the MSI redirection hint
bit. The RH bit is used in logical destination mode to indicate that
the delivery of the interrupt shall only be to the lowest priority
candidate LAPIC.

Currently, there is no handling of the MSI RH bit. This patch implements 
the following logic:

* DM=0, RH=*  : Physical destination mode. Interrupt is delivered to
                    the LAPIC with the matching APIC ID. (Subject to
                    the usual restrictions, i.e. no broadcast dest)
* DM=1, RH=0  : Logical destination mode without redirection. Interrupt
                    is delivered to all LAPICs in the logical group 
                    specified by the IRQ's destination map and delivery
                    mode.
* DM=1, RH=1  : Logical destination mode with redirection. Interrupt
                    is delivered only to the lowest priority LAPIC in the 
                    logical group specified by the dest map and the
                    delivery mode. Delivery semantics are otherwise
                    specified by the delivery_mode of the IRQ, which
                    is unchanged.

These changes reflect those made in the KVM in
http://www.spinics.net/lists/kvm/msg114915.html ("kvm: x86: Implement
handling of RH=1 for MSI delivery in KVM"), which are under review but
are largely settled in terms of functionality.


James Sullivan (3):
  apic: Added helper function apic_match_dest,
    apic_match_[physical,logical]_dest
  apic: Set and pass in RH bit for MSI interrupts
  apic: Implement handling of RH=1 for MSI interrupt delivery

 hw/intc/apic.c         | 70 +++++++++++++++++++++++++++++++++++++-------------
 hw/intc/ioapic.c       |  2 +-
 include/hw/i386/apic.h |  3 ++-
 trace-events           |  2 +-
 4 files changed, 56 insertions(+), 21 deletions(-)

-- 
2.3.3