[PATCH 0/4] KVM: arm64: vgic: Locking fixes

[Jean-Philippe Brucker]

Another fun locking puzzle, between the new config_lock and srcu.
Patch 1 attempts to fix it, and the other patches fix simpler issues.

I got these lockdep reports while running KVM QEMU on a TCG QEMU, but it
can also be triggered by running the vgic_irq kselftest on TCG QEMU.
Now, with the fix and lockdep enabled, vgic_irq hangs but I believe it's
an unrelated weirdness: if I introduce a separate lockdep warning for
some made up locks, then the test passes again. So I'm sending this out
now for discussion, and will investigate that one later.

I run the host with:

qemu-system-aarch64 -M virt,virtualization=true,gic-version=3 -m 2G -smp 8 -cpu max -append 'console=hvc0 root=/dev/vda rw' -kernel Image -nodefaults -chardev stdio,mux=on,id=virtiocon0,signal=off -device virtio-serial-device -device virtconsole,chardev=virtiocon0 -mon chardev=virtiocon0,mode=readline -device virtio-blk-device,drive=hd0 -drive format=raw,if=none,file=virt_root.bin,id=hd0 -nographic

Jean-Philippe Brucker (4):
  KVM: arm64: vgic: Fix a circular locking issue
  KVM: arm64: vgic: Wrap vgic_its_create() with config_lock
  KVM: arm64: vgic: Fix locking comment
  KVM: arm64: vgic: Fix a comment

 arch/arm64/kvm/vgic/vgic-init.c       | 27 +++++++++++++++++------
 arch/arm64/kvm/vgic/vgic-its.c        | 14 ++++++++----
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 10 +++++++--
 arch/arm64/kvm/vgic/vgic-mmio-v3.c    | 31 ++++++++++++++++++---------
 arch/arm64/kvm/vgic/vgic-mmio.c       |  8 ++-----
 arch/arm64/kvm/vgic/vgic-v2.c         |  6 ------
 arch/arm64/kvm/vgic/vgic-v3.c         |  7 ------
 arch/arm64/kvm/vgic/vgic-v4.c         |  3 ++-
 8 files changed, 64 insertions(+), 42 deletions(-)

-- 
2.40.0