[Qemu-devel] [PATCH v4 00/16] IOMMU: Enable interrupt remapping for Intel IOMMU

[Peter Xu]

Jan, Michael,

Still haven't got your response from v3 review comments, but I
decided to move on to provide a workable version first (v3 is
missing the first patch, so it is not working). Also, misc issues
are addressed from Radim. Anyway, I am always ready for v5 and
further. :)

Github branch for your reference in case needed:

  https://github.com/xzpeter/qemu vtd-intr-v4

Thanks,

v4 changes (all patch number corresponds to v3):
- add one patch at the start of v3 series: I missed to send the
  first patch in v3. adding it in. [Jan]
- patch 9: add support for compatible mode (no reason not to support
  it, if not, we will get some warnings when using split irqchip)
- patch 11: further simplify ioapic_update_kvm_routes() using the
  helper function.
- patch 12: tweak on kvm_arch_fixup_msi_route() rather than
  ioapic_update_kvm_routes() only. [Radim]
- add patch 15: introduce IEC (Interrupt Entry Cache) invalidation
  notifier list. We can register to this list if we want to be
  notified when we got IR invalidation requests [Radim]
- add patch 16: let IOAPIC the first consumer for the above IEC
  notifier list. [Radim]
- several other trivial fixes (like moving some defines from .c to
  .h, moving several lines of changes from one patch to another to
  make it make more sense, etc.)

v3 changes (all patch numbers corresponds to v2):
- patch 1 (-> v3 patch 13)
  - move to the end of series [Alex]
- patch 10 (dropped)
  - drop this one, since re-worked on IOAPIC support, so we do not
    need this any more.
- patch 12 (-> v3 patch 10)
  - leverage MSI path for IOAPIC IR [Jan]
- patch 13 (v3 -> patch 9)
  - remove vtd_interrupt_remap_msi() declaration by reordering the
    functions [mst]
  - vtd_generate_msi_message(): init msg using {}, remove FIXME
    [mst]
- new patches
  - v3 patch 11: introduce ioapic_entry_parse() helper function
  - v3 patch 12: add support for kernel-irqchip=split. This needs
    more reviews, logically this should enable lots of things:
        splitted irqchip, irqfd, vhost, and irqfd support for
        passthrough devices (not tested). Please refer to the patch for
        more information.

v2 changes:
- patch 1
  - rename "int_remap" to "intr" in several places [Marcel]
  - remove "Intel" specific words in desc or commit message, prepare
    itself with further AMD support [Marcel]
  - avoid using object_property_get_bool() [Marcel]
- patch 5
  - use PCI bus number 0xff rather than 0xf0 for the IOAPIC scope
    definition. (please let me know if anyone knows how I can avoid
        user using PCI bus number 0xff... TIA)
- patch 11
  - fix comments [Marcel]
- all
  - remove intr_supported variable [Marcel]

This patchset provide very basic functionalities for interrupt
remapping (IR) support of the emulated Intel IOMMU device.

By default, IR is disabled to be better compatible with current
QEMU. To enable IR, we can using the following command to boot a
IR-supported VM with virtio-net device with vhost (still do not
support kvm-ioapic, so we need to specify kernel-irqchip={split|off}
here):

$ qemu-system-x86_64 -M q35,iommu=on,intr=on,kernel-irqchip=split \
     -enable-kvm -m 1024 \
         -netdev tap,id=net0,vhost=on \
     -device virtio-net-pci,netdev=user.0 \
     -monitor telnet::3333,server,nowait \
         /var/lib/libvirt/images/vm1.qcow2

When guest boots, we can verify whether IR enabled by grepping the
dmesg like:

address@hidden ~]# journalctl -k | grep "DMAR-IR"
Feb 19 11:21:23 localhost.localdomain kernel: DMAR-IR: IOAPIC id 0 under DRHD 
base  0xfed90000 IOMMU 0
Feb 19 11:21:23 localhost.localdomain kernel: DMAR-IR: Enabled IRQ remapping in 
xapic mode

Currently supported devices:

- Emulated/Splitted irqchip
- Generic PCI Devices
- vhost devices
- pass through device support? Not tested, but suppose it should work.

TODO List:

- kvm-ioapic support (?)
- EIM support
- IR fault reporting
- source-id validation for IRTE
- IRTE cache and better queued invalidation
- migration support (for IOMMU as general?)
- more?

Peter Xu (16):
  acpi: enable INTR for DMAR report structure
  intel_iommu: allow queued invalidation for IR
  intel_iommu: set IR bit for ECAP register
  acpi: add DMAR scope definition for root IOAPIC
  intel_iommu: define interrupt remap table addr register
  intel_iommu: handle interrupt remap enable
  intel_iommu: define several structs for IOMMU IR
  intel_iommu: provide helper function vtd_get_iommu
  intel_iommu: add IR translation faults defines
  intel_iommu: Add support for PCI MSI remap
  q35: ioapic: add support for emulated IOAPIC IR
  ioapic: introduce ioapic_entry_parse() helper
  intel_iommu: add support for split irqchip
  q35: add "int-remap" flag to enable intr
  intel_iommu: introduce IEC notifiers
  ioapic: register VT-d IEC invalidate notifier

 hw/core/machine.c                 |  22 +++
 hw/i386/acpi-build.c              |  36 ++--
 hw/i386/intel_iommu.c             | 376 +++++++++++++++++++++++++++++++++++++-
 hw/i386/intel_iommu_internal.h    |  47 ++++-
 hw/i386/pc.c                      |   3 +
 hw/intc/ioapic.c                  | 125 ++++++++-----
 hw/pci-host/q35.c                 |   4 +
 include/hw/acpi/acpi-defs.h       |  15 ++
 include/hw/boards.h               |   1 +
 include/hw/i386/apic-msidef.h     |   1 +
 include/hw/i386/intel_iommu.h     | 145 +++++++++++++++
 include/hw/i386/ioapic_internal.h |   1 +
 include/hw/i386/pc.h              |   4 +
 include/hw/pci-host/q35.h         |   9 +
 target-i386/kvm.c                 |  24 +++
 15 files changed, 754 insertions(+), 59 deletions(-)

-- 
2.4.3