Handle forwarded level-triggered interrupts

From: Christoffer Dall <[email protected]>

This series is an alternative approach to Eric Auger's direct EOI setup patches [1] in terms of the KVM VGIC support.

The idea is to maintain existing semantics for the VGIC for mapped level-triggered IRQs and also support the timer using mapped IRQs with the same VGIC support as VFIO interrupts.

Based on v4.15-rc.

Also available at:
git://git.kernel.org/pub/scm/linux/kernel/git/cdall/linux.git level-mapped-v6

Changes since v5:
- Rebased on v4.15-rc1
- Changed comment on preemption code as suggested by Andre
- Fixed white space and confusing conditionals as suggested by Drew

Changes since v4:
- Rebased on the timer optimization series merged in the v4.15 merge window, which caused a fair amount of modifications to patch 3.
- Added a static key to disable the sync operations when no VMs are using userspace irqchips to further optimize the performance
- Fixed extra semicolon in vgic-mmio.c
- Added commentary as requested during review
- Dropped what was patch 4, because it was merged as part of GICv4 support.
- Factored out the VGIC input level function change as separate patch (helps bisect and debugging), before providing a function for the timer.

Changes since v3:
- Added a number of patches and moved patches around a bit.
- Check for uaccesses in the mmio handler functions
- Fixed bugs in the mmio handler functions

Changes since v2:
- Removed patch 5 from v2 and integrating the changes in what's now patch 5 to make it easier to reuse code when adding VFIO integration.
- Changed the virtual distributor MMIO handling to use the pending_latch and more closely match the semantics of SPENDR and CPENDR for both level and edge mapped interrupts.

Changes since v1:
- Added necessary changes to the timer (Patch 1)
- Added handling of guest MMIO accesses to the virtual distributor (Patch 4)
- Addressed Marc's comments from the initial RFC (mostly renames)

Thanks,
-Christoffer

Christoffer Dall (8):
KVM: arm/arm64: Remove redundant preemptible checks
KVM: arm/arm64: Factor out functionality to get vgic mmio
requester_vcpu
KVM: arm/arm64: Don't cache the timer IRQ level
KVM: arm/arm64: vgic: Support level-triggered mapped interrupts
KVM: arm/arm64: Support a vgic interrupt line level sample function
KVM: arm/arm64: Support VGIC dist pend/active changes for mapped IRQs
KVM: arm/arm64: Provide a get_input_level for the arch timer
KVM: arm/arm64: Avoid work when userspace iqchips are not used

 include/kvm/arm_arch_timer.h  |   2 +
 include/kvm/arm_vgic.h        |  13 ++++-
 virt/kvm/arm/arch_timer.c     | 105 +++++++++++++++++++++-----------------
 virt/kvm/arm/arm.c            |   2 -
 virt/kvm/arm/vgic/vgic-mmio.c | 115 ++++++++++++++++++++++++++++++++++--------
 virt/kvm/arm/vgic/vgic-v2.c   |  29 +++++++++++
 virt/kvm/arm/vgic/vgic-v3.c   |  29 +++++++++++
 virt/kvm/arm/vgic/vgic.c      |  42 +++++++++++++--
 virt/kvm/arm/vgic/vgic.h      |   8 +++
 9 files changed, 270 insertions(+), 75 deletions(-)

2.14.2