[PATCH v2 0/4] LoongArch: KVM: irqchip fixes

[Tao Cui <cui.tao@linux.dev>]

From: Tao Cui <cuitao@kylinos.cn>

Hi,

Four fixes for the LoongArch KVM irqchip code:

- Patch 1 clears the device pointer in the destroy callbacks: when
  KVM_CREATE_DEVICE succeeds but the following fd allocation fails
  (e.g. under RLIMIT_NOFILE), ops->destroy() frees the irqchip while
  kvm->arch.* still points to it.

- Patch 2 loads kvm->arch.dmsintc once in the MSI injection path:
  pch_msi_set_irq() re-reads the pointer between the non-NULL check
  and the address-window comparison, so a concurrent device removal
  can be observed between them.

- Patch 3 aligns kvm_pch_pic_create() with kvm_eiointc_create() by
  propagating the real error code; the kvm_ipi_create() counterpart is
  being fixed separately (Chaithanya Lagisetty).

- Patch 4 rejects repeated PCH-PIC CTRL_INIT with -EEXIST, tracking
  the state with a has_init flag so the check and the MMIO base update
  are atomic under slots_lock.

All patches carry Fixes tags.

Changes in v2:

- Drop "Guard against NULL irqchip in irq injection" (v1 patch 2) and
  "Rebase steal time counter in vcpu context" (v1 patch 4) after
  review discussion: their trigger scenarios are not reachable
  through real VMM behaviour.

- Use the one-line destroy style in dmsintc suggested by Bibo.

- Track repeated PCH-PIC CTRL_INIT with a has_init flag and return
  -EEXIST instead of -EBUSY, also suggested by Bibo; move the check
  and base update under slots_lock so they are atomic.

- Add READ_ONCE() to the dmsintc pointer loads so the compiler
  keeps each of them a single load.

Tao Cui (4):
  LoongArch: KVM: Clear device pointer in irqchip destroy callbacks
  LoongArch: KVM: Load dmsintc pointer once in pch_msi_set_irq
  LoongArch: KVM: Propagate real error code in kvm_pch_pic_create
  LoongArch: KVM: Reject repeated PCH-PIC CTRL_INIT

 arch/loongarch/include/asm/kvm_pch_pic.h |  1 +
 arch/loongarch/kvm/intc/dmsintc.c        |  7 ++++++-
 arch/loongarch/kvm/intc/eiointc.c        |  1 +
 arch/loongarch/kvm/intc/ipi.c            |  1 +
 arch/loongarch/kvm/intc/pch_pic.c        | 22 ++++++++++++++++------
 5 files changed, 25 insertions(+), 7 deletions(-)

-- 
2.43.0