Re: [PATCH v23 00/14] KVM: arm64: CCA: Add basic plumbing for Realms

[Fuad Tabba]

Hi Marc,

On Fri, 09 Oct 2026 14:28:03 +0100, Marc Zyngier <maz@xxxxxxxxxx> wrote:
[...]
> Of course, mmu.c is where the crap happens, so anyone with any interest
> in this stuff being halfway sane, please review the conflict resolution.

I went through the mmu.c resolution and it looks good to me. Unmap and
aging are still no-ops for protected VMs, their abort handler is
unchanged, and the default op keeps the tracked unmap for nested MMUs.
Two minor things you might want to tidy up.

kvm_vm_stage2_unmap_range() repeats the lockdep_assert_held_write()
and WARN_ON(size & ~PAGE_MASK) that kvm_stage2_unmap_range() already
does before calling the op.

The VM_WARN_ON_ONCE() in kvm_vm_mem_abort() reads the ESR from the
vcpu again, where next had moved these checks to s2fd->esr. It's the
same result today, since the only caller handles a real abort, but
this (and dropping the vcpu local) would keep it in line with the
rest:

        VM_WARN_ON_ONCE(kvm_s2_fault_is_perm(s2fd) &&
                        !esr_abt_is_write_fault(s2fd->esr) &&
                        !kvm_s2_fault_is_exec(s2fd));

Cheers,
/fuad