[RFC PATCH 00/19] GICv4 Support for Xen

[Mykyta Poturai <Mykyta_Poturai@xxxxxxxx>]

This series introduces GICv4 direct LPI injection for Xen.

Direct LPI injection relies on the GIC tracking the mapping between physical and
virtual CPUs. Each VCPU requires a VPE that is created and registered with the
GIC via the `VMAPP` ITS command. The GIC is then informed of the current
VPE-to-PCPU placement by programming `VPENDBASER` and `VPROPBASER` in the
appropriate redistributor. LPIs are associated with VPEs through the `VMAPTI`
ITS command, after which the GIC handles delivery without trapping into the
hypervisor for each interrupt.

When a VPE is not scheduled but has pending interrupts, the GIC raises a per-VPE
doorbell LPI. Doorbells are owned by the hypervisor and prompt rescheduling so
the VPE can drain its pending LPIs.

Because GICv4 lacks a native doorbell invalidation mechanism, this series
includes a helper that invalidates doorbell LPIs via synthetic “proxy” devices,
following the approach used until GICv4.1.

All of this work is mostly based on the work of Penny Zheng
<penny.zheng@xxxxxxx> and Luca Fancellu <luca.fancellu@xxxxxxx>. And also from
Linux patches by Mark Zyngier.

Some patches are still a little rough and need some styling fixes and more
testing, as all of them needed to be carved line by line from a giant ~4000 line
patch. This RFC is directed mostly to get a general idea if the proposed
approach is suitable and OK with everyone. And there is still an open question
of how to handle Signed-off-by lines for Penny and Luca, since they have not
indicated their preference yet.

Mykyta Poturai (19):
  arm/gicv4 add management structure definitions
  arm/gicv4-its: Add GICv4 ITS command definitions
  arm/its: Export struct its_device
  arm/its: Add vlpi configuration
  arm/irq: Add hw flag to pending_irq
  arm/gicv4-its: Add VLPI map/unmap operations
  xen/domain: Alloc enough pages for VCPU struct
  arm/gic: Keep track of GIC features
  arm/its: Implement LPI invalidation
  arm/its: Keep track of BASER regs
  arm/its: Add ITS VM and VPE allocation/teardown
  arm/gic: Add VPENDBASER/VPROPBASER accessors
  arm/gic: VPE scheduling
  arm/its: VPE affinity changes
  arm: Add gicv4 to domain creation
  arm/gic: Fix LR group handling for GICv4
  arm/gicv4: Handle doorbells
  arm/gic: Add VPE proxy support
  arm/gicv4: Add GICv4 to the build system

 xen/arch/arm/Kconfig                   |    6 +
 xen/arch/arm/Makefile                  |    1 +
 xen/arch/arm/dom0less-build.c          |    1 +
 xen/arch/arm/domain.c                  |   16 +
 xen/arch/arm/gic-v2.c                  |    2 +-
 xen/arch/arm/gic-v3-its.c              |  339 +++++--
 xen/arch/arm/gic-v3-lpi.c              |  169 +++-
 xen/arch/arm/gic-v3.c                  |  215 ++++-
 xen/arch/arm/gic-v4-its.c              | 1136 ++++++++++++++++++++++++
 xen/arch/arm/gic-vgic.c                |    6 +
 xen/arch/arm/include/asm/gic.h         |    4 +-
 xen/arch/arm/include/asm/gic_v3_defs.h |   22 +
 xen/arch/arm/include/asm/gic_v3_its.h  |  139 ++-
 xen/arch/arm/include/asm/gic_v4_its.h  |  114 +++
 xen/arch/arm/include/asm/vgic.h        |   79 +-
 xen/arch/arm/vgic-v3-its.c             |   60 +-
 xen/arch/arm/vgic.c                    |   37 +-
 xen/common/domain.c                    |   14 +-
 xen/include/public/arch-arm.h          |    2 +
 19 files changed, 2174 insertions(+), 188 deletions(-)
 create mode 100644 xen/arch/arm/gic-v4-its.c
 create mode 100644 xen/arch/arm/include/asm/gic_v4_its.h

-- 
2.51.2