[PATCH v3 00/32] irqchip/gic-v4: GICv4.1 architecture support

Marc Zyngier
2019-12-24T11:11:23Z

[All I want for Christmas is... another monster GIC series!]

This rather long series expands the existing GICv4 support to deal with the
new GICv4.1 architecture, which comes with a set of major improvements
compared to v4.0:

- One architectural doorbell per vcpu, instead of one doorbell per VLPI

- Doorbell entirely managed by the HW, with an "at most once" delivery
guarantee per non-residency phase and only when requested by the
hypervisor

- A shared memory scheme between ITSs and redistributors, allowing for an
optimised residency sequence (the use of VMOVP becomes less frequent)

- Support for direct virtual SGI delivery (the injection path still involves
the hypervisor), at the cost of losing the active state on SGIs. It
shouldn't be a big deal, but some guest operating systems might notice
(Linux definitely won't care).

On the other hand, public documentation is not available yet, so that's a
bit annoying...

The series is roughly organised in 5 parts:

(1) Feature detection, errata workaround for TX1
(2) VPE table allocation, new flavours of VMAPP/VMOVP commands
(3) v4.1 doorbell management
(4) Virtual SGI support
(5) Plumbing of virtual SGIs in KVM

Ideally, I'd like to start merging some of this into 5.6.

Notes:

- This series has uncovered a behaviour that looks like a HW bug on
the Cavium ThunderX (aka TX1) platform (see patch #3). I'd very
much welcome some clarification from the Marvell/Cavium folks on
Cc, as well as an official erratum number if this happens to be an
actual bug.

[v3 update]
People have ignored for two months now, and it is fairly obvious
that support for this machine is slowly bit-rotting. Maybe I'll
drop the patch and instead start the process of removing all TX1
support from the kernel (we'd certainly be better off without it).

* From v2 [2]:
- Another bunch of fixes thanks to Zenghui Yu's very careful review
- HW-accelerated SGIs are now optional thanks to new architected
discovery/selection bits exposed by KVM and used by the guest kernel
- Rebased on v5.5-rc2

* From v1 [1]:
- A bunch of minor reworks after Zenghui Yu's review
- A workaround for what looks like a new and unexpected TX1 bug
- A subtle reorder of the series so that some patches can go in early

[1] https://lore.kernel.org/lkml/20190923182606.32100-1-maz@kernel.org/
[2] https://lore.kernel.org/lkml/20191027144234.8395-1-maz@kernel.org/

Marc Zyngier (32):
irqchip/gic-v3: Detect GICv4.1 supporting RVPEID
irqchip/gic-v3: Add GICv4.1 VPEID size discovery
irqchip/gic-v3: Workaround Cavium TX1 erratum when reading GICD_TYPER2
irqchip/gic-v3: Use SGIs without active state if offered
irqchip/gic-v4.1: VPE table (aka GICR_VPROPBASER) allocation
irqchip/gic-v4.1: Implement the v4.1 flavour of VMAPP
irqchip/gic-v4.1: Don't use the VPE proxy if RVPEID is set
irqchip/gic-v4.1: Implement the v4.1 flavour of VMOVP
irqchip/gic-v4.1: Plumb skeletal VPE irqchip
irqchip/gic-v4.1: Add mask/unmask doorbell callbacks
irqchip/gic-v4.1: Add VPE residency callback
irqchip/gic-v4.1: Add VPE eviction callback
irqchip/gic-v4.1: Add VPE INVALL callback
irqchip/gic-v4.1: Suppress per-VLPI doorbell
irqchip/gic-v4.1: Allow direct invalidation of VLPIs
irqchip/gic-v4.1: Advertise support v4.1 to KVM
irqchip/gic-v4.1: Map the ITS SGIR register page
irqchip/gic-v4.1: Plumb skeletal VSGI irqchip
irqchip/gic-v4.1: Add initial SGI configuration
irqchip/gic-v4.1: Plumb mask/unmask SGI callbacks
irqchip/gic-v4.1: Plumb get/set_irqchip_state SGI callbacks
irqchip/gic-v4.1: Plumb set_vcpu_affinity SGI callbacks
irqchip/gic-v4.1: Move doorbell management to the GICv4 abstraction
layer
irqchip/gic-v4.1: Add VSGI allocation/teardown
irqchip/gic-v4.1: Add VSGI property setup
irqchip/gic-v4.1: Eagerly vmap vPEs
KVM: arm64: GICv4.1: Let doorbells be auto-enabled
KVM: arm64: GICv4.1: Add direct injection capability to SGI registers
KVM: arm64: GICv4.1: Allow SGIs to switch between HW and SW interrupts
KVM: arm64: GICv4.1: Plumb SGI implementation selection in the
distributor
KVM: arm64: GICv4.1: Reload VLPI configuration on distributor
enable/disable
KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfs

arch/arm/include/asm/arch_gicv3.h | 2 +
arch/arm64/include/asm/arch_gicv3.h | 1 +
arch/arm64/include/asm/kvm_host.h | 1 +
drivers/irqchip/irq-gic-v3-its.c | 996 +++++++++++++++++++++++--
drivers/irqchip/irq-gic-v3.c | 57 +-
drivers/irqchip/irq-gic-v4.c | 134 +++-
include/kvm/arm_vgic.h | 4 +
include/linux/irqchip/arm-gic-common.h | 2 +
include/linux/irqchip/arm-gic-v3.h | 76 +-
include/linux/irqchip/arm-gic-v4.h | 43 +-
virt/kvm/arm/arm.c | 8 +
virt/kvm/arm/vgic/vgic-debug.c | 14 +-
virt/kvm/arm/vgic/vgic-mmio-v3.c | 68 +-
virt/kvm/arm/vgic/vgic-mmio.c | 88 ++-
virt/kvm/arm/vgic/vgic-v3.c | 3 +
virt/kvm/arm/vgic/vgic-v4.c | 139 +++-
virt/kvm/arm/vgic/vgic.h | 1 +
17 files changed, 1522 insertions(+), 115 deletions(-)

--
2.20.1