[PATCH 00/43] KVM: arm64: Add GICv5 IRS support

Sascha Bischoff
2026-04-27T16:07:15Z

Hi all,

This series builds on the initial vGICv5 support [1] and adds support
for the GICv5 IRS, as described by the GICv5 (EAC0) specification [2].
With this, a GICv5 guest is no longer restricted to PPIs, and can
make use of SPIs and LPIs as well.

With SPIs and LPIs available, this series makes it possible to boot a
full Linux guest on the Arm FVP model [3], using the setup described
in Lorenzo's GICv5 Linux software enablement guide [4]. In addition,
GICv5 IPIs are typically implemented as LPIs, so LPI support is what
makes guests with more than one vCPU possible.

The corresponding kvmtool changes are available separately [5]. With
these changes, `--irqchip=gicv5` works now. The `--irqchip=gicv5-its`
configuration does not work with this series, as ITS/MSI support is not
included here.

The IRS is created as part of the vgic-v5 device, and is not a
separate KVM device. This is because implementing the CPU interface
alone would limit a guest to a single vCPU and PPIs only. Hence, the
IRS is bundled into the VGIC, much like the distributor for GICv3.

The series adds the host-side plumbing needed for KVM to interact with
the physical IRS, including VM and VPE table management, VPE residency,
and VPE doorbells. It also adds an emulated IRS MMIO interface for the
guest, together with the UAPI needed for userspace to configure the IRS
address and to save/restore the IRS and IST state.

The main pieces are:

* Host IRS capability discovery and configuration frame plumbing.

* Allocation and management of the GICv5 VM table, VPE table, VMTEs,
VPEs, and guest IST backing storage.

* VPE residency and doorbell handling, allowing the IRS to select SPIs
and LPIs for resident VPEs and wake non-resident VPEs when required.

* Emulation of the GICv5 IRS MMIO CONFIG_FRAME for guests.
Virtualisation, MPAM, MEC, SWERR are not supported and are RAZ/WI.

* SPI injection support using GIC VDPEND, together with tracking of
in-flight SPIs so that deactivation notifiers can still be handled.

* Save/restore support for GICv5 EL1 system registers, IRS MMIO state,
and guest ISTs.

* Documentation for the new VGICv5 IRS userspace interfaces and the
required save/restore ordering.

Please pay close attention to the save/restore interface and ordering,
in particular to make sure that no guest state has been omitted.

LPIs are explicitly driven by the guest through the IRS/IST state. This
series does not add direct LPI injection support, and does not add MSI
support. It also does not add GICv5 ITS emulation.

These changes are based on v7.1-rc1. They presume the existence of the
still-under-review changes in [6]. I've pushed the full set of changes
to a branch at [7].

Thanks for taking the time to look at these changes. Apologies for the
size of the series, but this is a rather hard set to disentangle and
review separately!

Thanks,
Sascha

[1] https://lore.kernel.org/all/20260319154937.3619520-1-sascha.bischoff@arm.com/
[2] https://developer.arm.com/documentation/aes0070/latest
[3] https://developer.arm.com/documentation/108086/latest
[4] https://linaro.atlassian.net/wiki/x/CQAF-wY
[5] https://lore.kernel.org/all/20260116182606.61856-1-sascha.bischoff@arm.com/
[6] https://lore.kernel.org/all/20260415115559.2227718-1-maz@kernel.org/
[7] https://gitlab.arm.com/linux-arm/linux-sb/-/tree/gicv5_kvm_irs_support

Sascha Bischoff (43):
arm64/sysreg: Add GICv5 GIC VDPEND and VDRCFG encodings
arm64/sysreg: Update ICC_CR0_EL1 with LINK and LINK_IDLE fields
KVM: arm64: gic-v5: Add resident/non-resident hyp calls
irqchip/gic-v5: Provide IRS config frame attrs to KVM
KVM: arm64: gic-v5: Extract host IRS caps from IRS config frame
KVM: arm64: gic-v5: Add VPE doorbell domain
KVM: arm64: gic-v5: Create & manage VM and VPE tables
KVM: arm64: gic-v5: Introduce guest IST alloc and management
KVM: arm64: gic-v5: Implement VMT/vIST IRS MMIO Ops
KVM: arm64: gic-v5: Implement VPE IRS MMIO Ops
KVM: arm64: gic-v5: Make VPEs valid in vgic_v5_reset()
KVM: arm64: gic-v5: Clear db_fired flag before making VPE non-resident
KVM: arm64: gic-v5: Make VPEs (non-)resident in vgic_load/put
KVM: arm64: gic-v5: Request VPE doorbells when going non-resident
KVM: arm64: gic-v5: Handle doorbells in kvm_vgic_vcpu_pending_irq()
KVM: arm64: gic-v5: Initialise and teardown VMTEs & doorbells
KVM: arm64: gic-v5: Enable VPE DBs on VPE reset and disable on
teardown
KVM: arm64: gic-v5: Define remaining IRS MMIO registers
KVM: arm64: gic-v5: Introduce struct vgic_v5_irs and IRS base address
KVM: arm64: gic-v5: Add IRS IODEV to iodev_types and generic MMIO
handlers
KVM: arm64: gic-v5: Add KVM_VGIC_V5_ADDR_TYPE_IRS to UAPI
KVM: arm64: gic-v5: Add GICv5 IRS IODEV and MMIO emulation
KVM: arm64: gic-v5: Set IRICHPPIDIS based on IRS enable state
KVM: arm64: gic-v5: Call IRS init/teardown from vgic_v5 init/teardown
KVM: arm64: gic-v5: Register the IRS IODEV
Documentation: KVM: Extend VGICv5 docs for KVM_VGIC_V5_ADDR_TYPE_IRS
KVM: arm64: selftests: Update vGICv5 selftest to set IRS address
KVM: arm64: gic-v5: Introduce SPI AP list
KVM: arm64: gic-v5: Add GIC VDPEND and GIC VDRCFG hyp calls
KVM: arm64: gic-v5: Track SPI state for in-flight SPIs
KVM: arm64: gic: Introduce set_pending_state() to irq_op
KVM: arm64: gic-v5: Support SPI injection
KVM: arm64: gic-v5: Add GICv5 SPI injection to irqfd
KVM: arm64: gic-v5: Mask per-vcpu PPI state in
vgic_v5_finalize_ppi_state()
KVM: arm64: gic-v5: Add GICv5 EL1 sysreg userspace set/get interface
KVM: arm64: gic-v5: Implement save/restore mechanisms for ISTs
KVM: arm64: gic-v5: Handle userspace accesses to IRS MMIO region
KVM: arm64: gic-v5: Add VGIC_GRP_IRS_REGS/VGIC_GRP_IST to UAPI
KVM: arm64: gic-v5: Plumb in has/set/get_attr for sysregs & IRS MMIO
regs
Documentation: KVM: Document KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS for
VGICv5
Documentation: KVM: Add KVM_DEV_ARM_VGIC_GRP_IRS_REGS to VGICv5 docs
Documentation: KVM: Add docs for KVM_DEV_ARM_VGIC_GRP_IST
Documentation: KVM: Add the VGICv5 IRS save/restore sequences

.../virt/kvm/devices/arm-vgic-v5.rst | 224 ++-
arch/arm64/include/asm/kvm_asm.h | 4 +
arch/arm64/include/asm/kvm_hyp.h | 4 +
arch/arm64/include/asm/sysreg.h | 18 +-
arch/arm64/include/uapi/asm/kvm.h | 7 +
arch/arm64/kvm/Makefile | 3 +-
arch/arm64/kvm/arm.c | 2 +-
arch/arm64/kvm/hyp/nvhe/hyp-main.c | 33 +
arch/arm64/kvm/hyp/vgic-v5-sr.c | 54 +
arch/arm64/kvm/sys_regs.c | 6 +-
arch/arm64/kvm/vgic-sys-reg-v5.c | 510 +++++
arch/arm64/kvm/vgic/vgic-init.c | 57 +-
arch/arm64/kvm/vgic/vgic-irqfd.c | 13 +-
arch/arm64/kvm/vgic/vgic-irs-v5.c | 1075 ++++++++++
arch/arm64/kvm/vgic/vgic-kvm-device.c | 235 ++-
arch/arm64/kvm/vgic/vgic-mmio.c | 6 +
arch/arm64/kvm/vgic/vgic-mmio.h | 2 +
arch/arm64/kvm/vgic/vgic-v5-tables.c | 1766 +++++++++++++++++
arch/arm64/kvm/vgic/vgic-v5-tables.h | 212 ++
arch/arm64/kvm/vgic/vgic-v5.c | 1250 +++++++++++-
arch/arm64/kvm/vgic/vgic.c | 25 +-
arch/arm64/kvm/vgic/vgic.h | 20 +-
arch/arm64/tools/sysreg | 4 +-
drivers/irqchip/irq-gic-v5-irs.c | 26 +
drivers/irqchip/irq-gic-v5.c | 3 +
include/kvm/arm_vgic.h | 126 +-
include/linux/irqchip/arm-gic-v5.h | 199 +-
include/linux/irqchip/arm-vgic-info.h | 5 +
tools/arch/arm64/include/uapi/asm/kvm.h | 2 +
tools/testing/selftests/kvm/arm64/vgic_v5.c | 6 +
.../selftests/kvm/include/arm64/gic_v5.h | 3 +
31 files changed, 5791 insertions(+), 109 deletions(-)
create mode 100644 arch/arm64/kvm/vgic-sys-reg-v5.c
create mode 100644 arch/arm64/kvm/vgic/vgic-irs-v5.c
create mode 100644 arch/arm64/kvm/vgic/vgic-v5-tables.c
create mode 100644 arch/arm64/kvm/vgic/vgic-v5-tables.h

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2.34.1