Add a module param, enable_device_posted_irqs, to control and enumerate
KVM support for device posted IRQs.

v3:
 - Put the module param in vendor code to avoid issue with reloading vendor
   modules, and to match enable_apicv (and enable_ipiv in the future).
 - Fix a shortlog typo. [Jim]

v2:
 - https://lore.kernel.org/all/20250320142022.766201-1-seanjc@google.com
 - Add prep patches to use kvm_arch_has_irq_bypass() in vendor code when
   querying support IRQ bypass, a.k.a. device posted IRQs, so as not to
   unexpectedly introduce a (desired) dependency on enable_apicv. [Yosry]
 - Use "&=" when constraining enable_device_posted_irqs based on APICv
   and IOMMU posting support. [Yosry]

v1: https://lore.kernel.org/all/20250315025615.2367411-1-seanjc@google.com

Sean Christopherson (3):
  KVM: VMX: Don't send UNBLOCK when starting device assignment without
    APICv
  KVM: SVM: Don't update IRTEs if APICv/AVIC is disabled
  KVM: x86: Add module param to control and enumerate device posted IRQs

 arch/x86/include/asm/kvm_host.h | 1 +
 arch/x86/kvm/svm/avic.c         | 3 +--
 arch/x86/kvm/svm/svm.c          | 2 ++
 arch/x86/kvm/vmx/posted_intr.c  | 7 +++----
 arch/x86/kvm/vmx/vmx.c          | 2 ++
 arch/x86/kvm/x86.c              | 9 ++++++++-
 6 files changed, 17 insertions(+), 7 deletions(-)


base-commit: 782f9feaa9517caf33186dcdd6b50a8f770ed29b
-- 
2.49.0.472.ge94155a9ec-goog