KVM: x86: APIC and I/O APIC cleanups

[PATCH 0/9] KVM: x86: APIC and I/O APIC cleanups

Posted by Sean Christopherson 2 months ago

Drop a bunch of _really_ old dead code (ASSERT() buried behind a DEBUG
macro that probably hasn't been enabled in 15+ years), clean up the bizarre
and confusing "dest_map" pointer that gets passed all of the place but is
only actually used for in-kernel RTC emulation, and the bury almost all of
ioapic.h behind CONFIG_KVM_IOAPIC=y.

I'm not entirely sure why I started poking at this.  I think I got mad at
the dest_map code, and then things snowballed...

Sean Christopherson (9):
  KVM: x86: Drop ASSERT()s on APIC/vCPU being non-NULL
  KVM: x86: Drop guest/user-triggerable asserts on IRR/ISR vectors
  KVM: x86: Drop ASSERT() on I/O APIC EOIs being only for LEVEL_to
    WARN_ON_ONCE
  KVM: x86: Drop guest-triggerable ASSERT()s on I/O APIC access
    alignment
  KVM: x86: Drop MAX_NR_RESERVED_IOAPIC_PINS, use KVM_MAX_IRQ_ROUTES
    directly
  KVM: x86: Add a wrapper to handle common case of IRQ delivery without
    dest_map
  KVM: x86: Fold "struct dest_map" into "struct rtc_status"
  KVM: x86: Bury ioapic.h definitions behind CONFIG_KVM_IOAPIC
  KVM: x86: Hide KVM_IRQCHIP_KERNEL behind CONFIG_KVM_IOAPIC=y

 arch/x86/include/asm/kvm_host.h |  2 +
 arch/x86/kvm/hyperv.c           |  2 +-
 arch/x86/kvm/ioapic.c           | 43 ++++++++-------------
 arch/x86/kvm/ioapic.h           | 38 ++++++-------------
 arch/x86/kvm/irq.c              |  4 +-
 arch/x86/kvm/lapic.c            | 66 ++++++++++++++++-----------------
 arch/x86/kvm/lapic.h            | 20 +++++++---
 arch/x86/kvm/x86.c              |  4 +-
 arch/x86/kvm/xen.c              |  2 +-
 9 files changed, 81 insertions(+), 100 deletions(-)


base-commit: 5d3e2d9ba9ed68576c70c127e4f7446d896f2af2
-- 
2.52.0.223.gf5cc29aaa4-goog

Re: [PATCH 0/9] KVM: x86: APIC and I/O APIC cleanups

Posted by Sean Christopherson 3 weeks, 4 days ago

On Fri, 05 Dec 2025 16:43:02 -0800, Sean Christopherson wrote:
> Drop a bunch of _really_ old dead code (ASSERT() buried behind a DEBUG
> macro that probably hasn't been enabled in 15+ years), clean up the bizarre
> and confusing "dest_map" pointer that gets passed all of the place but is
> only actually used for in-kernel RTC emulation, and the bury almost all of
> ioapic.h behind CONFIG_KVM_IOAPIC=y.
> 
> I'm not entirely sure why I started poking at this.  I think I got mad at
> the dest_map code, and then things snowballed...
> 
> [...]

Applied to kvm-x86 apic, thanks!

[1/9] KVM: x86: Drop ASSERT()s on APIC/vCPU being non-NULL
      https://github.com/kvm-x86/linux/commit/a4978324e4bd
[2/9] KVM: x86: Drop guest/user-triggerable asserts on IRR/ISR vectors
      https://github.com/kvm-x86/linux/commit/37187992dd82
[3/9] KVM: x86: Drop ASSERT() on I/O APIC EOIs being only for LEVEL_to WARN_ON_ONCE
      https://github.com/kvm-x86/linux/commit/ca909f9ea8cb
[4/9] KVM: x86: Drop guest-triggerable ASSERT()s on I/O APIC access alignment
      https://github.com/kvm-x86/linux/commit/9eabb2a5e499
[5/9] KVM: x86: Drop MAX_NR_RESERVED_IOAPIC_PINS, use KVM_MAX_IRQ_ROUTES directly
      https://github.com/kvm-x86/linux/commit/4d846f183897
[6/9] KVM: x86: Add a wrapper to handle common case of IRQ delivery without dest_map
      https://github.com/kvm-x86/linux/commit/1a5d7f9540af
[7/9] KVM: x86: Fold "struct dest_map" into "struct rtc_status"
      https://github.com/kvm-x86/linux/commit/5cd6b1a6eebd
[8/9] KVM: x86: Bury ioapic.h definitions behind CONFIG_KVM_IOAPIC
      https://github.com/kvm-x86/linux/commit/59c3e0603d86
[9/9] KVM: x86: Hide KVM_IRQCHIP_KERNEL behind CONFIG_KVM_IOAPIC=y
      https://github.com/kvm-x86/linux/commit/fd09d259c161

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https://github.com/kvm-x86/linux/tree/next