Merge branch kvm-arm64/el2-feature-control into kvmarm-master/next

* kvm-arm64/el2-feature-control: (23 commits)
  : .
  : General rework of EL2 features that can be disabled to satisfy
  : the requirement of migration between heterogeneous hosts:
  :
  : - Handle effective RES0 behaviour of undefined registers, making sure
  :   that disabling a feature affects full registeres, and not just
  :   individual control bits. (20250918151402.1665315-1-maz@kernel.org)
  :
  : - Allow ID_AA64MMFR1_EL1.{TWED,HCX} to be disabled from userspace.
  :   (20250911114621.3724469-1-yangjinqian1@huawei.com)
  :
  : - Turn the NV feature management into a deny-list, and expose
  :   missing features to EL2 guests.
  :   (20250912212258.407350-1-oliver.upton@linux.dev)
  : .
  KVM: arm64: nv: Expose up to FEAT_Debugv8p8 to NV-enabled VMs
  KVM: arm64: nv: Advertise FEAT_TIDCP1 to NV-enabled VMs
  KVM: arm64: nv: Advertise FEAT_SpecSEI to NV-enabled VMs
  KVM: arm64: nv: Expose FEAT_TWED to NV-enabled VMs
  KVM: arm64: nv: Exclude guest's TWED configuration when TWE isn't set
  KVM: arm64: nv: Expose FEAT_AFP to NV-enabled VMs
  KVM: arm64: nv: Expose FEAT_ECBHB to NV-enabled VMs
  KVM: arm64: nv: Expose FEAT_RASv1p1 via RAS_frac
  KVM: arm64: nv: Expose FEAT_DF2 to NV-enabled VMs
  KVM: arm64: nv: Don't erroneously claim FEAT_DoubleLock for NV VMs
  KVM: arm64: nv: Convert masks to denylists in limit_nv_id_reg()
  KVM: arm64: selftests: Test writes to ID_AA64MMFR1_EL1.{HCX, TWED}
  KVM: arm64: Make ID_AA64MMFR1_EL1.{HCX, TWED} writable from userspace
  KVM: arm64: Convert MDCR_EL2 RES0 handling to compute_reg_res0_bits()
  KVM: arm64: Convert SCTLR_EL1 RES0 handling to compute_reg_res0_bits()
  KVM: arm64: Enforce absence of FEAT_TCR2 on TCR2_EL2
  KVM: arm64: Enforce absence of FEAT_SCTLR2 on SCTLR2_EL{1,2}
  KVM: arm64: Convert HCR_EL2 RES0 handling to compute_reg_res0_bits()
  KVM: arm64: Enforce absence of FEAT_HCX on HCRX_EL2
  KVM: arm64: Enforce absence of FEAT_FGT2 on FGT2 registers
  ...

Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --cc arch/arm64/kvm/nested.c
Simple merge