[PATCH v17 00/20] KVM: arm64: CCA: Add basic plumbing for Realms

[Fuad Tabba]

Hi Suzuki,

On Tue, 8 Sept 2026 at 17:22, Suzuki K Poulose <suzuki.poulose at arm.com> wrote:
...
>  3) NEW: Enlighten KVM arm64 about the different VM types and use call backs for
>    the VM type, rather than spilling the is_this_type_of_vm() everywhere. This is
>    not complete yet, but it is largely functional. Adds VCPU and Stage2 MMU related
>    callbacks with support for the existing VM types.

A design thought on the vm_flavor dispatch tables. They're
hand-maintained arrays indexed by enum, and a gap fails silently at
runtime, not at build: arm64_vm_s2_ops[] has no VM_REALM row, so a
realm VM would get NULL ops.

How about something like declaring it unsized with
BUILD_BUG_ON(ARRAY_SIZE(arm64_vm_s2_ops) != VM_FLAVOR_MAX), as
host_hcall does? A non-NULL check of the selected ops' mandatory
callbacks at VM init would catch the s2_ops naming typo Sashiko
caught, where the rows point at zeroed forward-declared structs.

Cheers,
/fuad