[PATCH v7 00/20] KVM GICv3 emulation

Andre Przywara andre.przywara at arm.com
Wed Jan 14 08:31:04 PST 2015

This is version 7 of the GICv3 guest emulation series.
As v6 this series is based on v3.19-rc3 plus Eric's explicit

Most visible change is that the v6 patch 18/20 (introduce
kvm_check_device_type()) is now gone, instead the validity check
for the GICv2 emulation is now done internally via a new member of
struct vgic_params (see new 18/20 for the implementation).
There is new patch (20/20) that checks the userland provided
memory regions's address for the VGIC to be properly aligned. Since
that is build upon a refactoring in the series, I put it at the end.
If this should be one of the first patches, let me know and I will
rework that.

The rest of the changes are smaller things spotted by Christoffer
(many thanks for the repeated, surely tiresome reviews!).

For a changelog summary see below, also each patch carries a
Only patches 02, 05, 08, 15, 18 and 19 had actual changes, 20/20 is

A git repo hosting all these patches lives in the kvm-gicv3/v7 branch
of [1]. The kvm-gicv3/v6 branch has been updated to hold the delta

GICv3 is the ARM generic interrupt controller designed to overcome
some limits of the prevalent GICv2. Most notably it lifts the 8-CPU
limit. Though with Linux-3.17 Marc introduced support for hosts to
use a GICv3, the CPU limitation still applies to KVM guests, since
the current code emulates a GICv2 only.
Also, GICv2 backward compatibility being optional in GICv3, a number
of systems won't be able to run GICv2 guests.

This patch series provides code to emulate a GICv3 distributor and
redistributor for any KVM guest. It requires a GICv3 in the host to
work. With those patches one can run guests efficiently on any GICv3
host. It has the following features:
- Affinity routing (support for up to 255 VCPUs, more possible)
- System registers (as opposed to MMIO access)
- No ITS
- No priority support (as the GICv2 emulation)
- No save / restore support so far (will be added soon)
- Only Group1 interrupts support

The first patches actually refactor the current VGIC code to make
room for a different VGIC model to be dropped in with Patch 15.
The remaining patches connect the new model to the kernel backend and
the userland facing code.

The series goes on top of v3.19-rc3 plus Eric's init rework patches.
The necessary patches for kvmtool to enable the guest's GICv3 have
been posted here before [2], an updated version will follow soon.

There was some testing on the fast model with some I/O and interrupt
affinity shuffling in a Linux guest with a varying number of VCPUs as
well as some testing on a Juno board (GICv2 only, to spot regressions).

Please review and test.
I would be grateful for people to test for GICv2 regressions also
(so on a GICv2 host with current kvmtool/qemu), as there is quite
some refactoring on that front.

Much of the code was inspired by MarcZ, also kudos to him for doing
the rather painful rebase on top of v3.17-rc1.


[1] https://github.com/apritzel/linux.git
[2] https://lists.cs.columbia.edu/pipermail/kvmarm/2014-June/010086.html

Andre Przywara (20):
  arm/arm64: KVM: rework MPIDR assignment and add accessors
  arm/arm64: KVM: pass down user space provided GIC type into vGIC code
  arm/arm64: KVM: refactor vgic_handle_mmio() function
  arm/arm64: KVM: wrap 64 bit MMIO accesses with two 32 bit ones
  arm/arm64: KVM: introduce per-VM ops
  arm/arm64: KVM: move kvm_register_device_ops() into vGIC probing
  arm/arm64: KVM: dont rely on a valid GICH base address
  arm/arm64: KVM: make the maximum number of vCPUs a per-VM value
  arm/arm64: KVM: make the value of ICC_SRE_EL1 a per-VM variable
  arm/arm64: KVM: refactor MMIO accessors
  arm/arm64: KVM: refactor/wrap vgic_set/get_attr()
  arm/arm64: KVM: add vgic.h header file
  arm/arm64: KVM: split GICv2 specific emulation code from vgic.c
  arm/arm64: KVM: add opaque private pointer to MMIO data
  arm/arm64: KVM: add virtual GICv3 distributor emulation
  arm64: GICv3: introduce symbolic names for GICv3 ICC_SGI1R_EL1 fields
  arm64: KVM: add SGI generation register emulation
  arm/arm64: KVM: enable kernel side of GICv3 emulation
  arm/arm64: KVM: allow userland to request a virtual GICv3
  arm/arm64: KVM: force alignment of VGIC dist/CPU/redist addresses

 Documentation/virtual/kvm/api.txt              |   13 +-
 Documentation/virtual/kvm/devices/arm-vgic.txt |   26 +-
 arch/arm/include/asm/kvm_emulate.h             |    5 +-
 arch/arm/include/asm/kvm_host.h                |    3 +
 arch/arm/include/asm/kvm_mmio.h                |    1 +
 arch/arm/kvm/Makefile                          |    1 +
 arch/arm/kvm/arm.c                             |   23 +-
 arch/arm/kvm/psci.c                            |   17 +-
 arch/arm64/include/asm/kvm_emulate.h           |    5 +-
 arch/arm64/include/asm/kvm_host.h              |    5 +
 arch/arm64/include/asm/kvm_mmio.h              |    1 +
 arch/arm64/include/uapi/asm/kvm.h              |    7 +
 arch/arm64/kernel/asm-offsets.c                |    1 +
 arch/arm64/kvm/Makefile                        |    2 +
 arch/arm64/kvm/sys_regs.c                      |   40 +-
 arch/arm64/kvm/vgic-v3-switch.S                |   14 +-
 drivers/irqchip/irq-gic-v3.c                   |   14 +-
 include/kvm/arm_vgic.h                         |   43 +-
 include/linux/irqchip/arm-gic-v3.h             |   44 +
 include/linux/kvm_host.h                       |    2 +
 include/uapi/linux/kvm.h                       |    2 +
 virt/kvm/arm/vgic-v2-emul.c                    |  847 ++++++++++++++++++
 virt/kvm/arm/vgic-v2.c                         |    4 +
 virt/kvm/arm/vgic-v3-emul.c                    | 1036 ++++++++++++++++++++++
 virt/kvm/arm/vgic-v3.c                         |   82 +-
 virt/kvm/arm/vgic.c                            | 1121 ++++++------------------
 virt/kvm/arm/vgic.h                            |  123 +++
 27 files changed, 2566 insertions(+), 916 deletions(-)
 create mode 100644 virt/kvm/arm/vgic-v2-emul.c
 create mode 100644 virt/kvm/arm/vgic-v3-emul.c
 create mode 100644 virt/kvm/arm/vgic.h


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