[PATCH 08/17] KVM: arm64: Kill topup_memcache from kvm_s2_fault

[Fuad Tabba]

Hi Marc,

On Mon, 16 Mar 2026 at 17:55, Marc Zyngier <maz at kernel.org> wrote:
>
> The topup_memcache field can be easily replaced by the equivalent
> conditions, and the resulting code is not much worse.
>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  arch/arm64/kvm/mmu.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 11820e39ad8e1..abe239752c696 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -1712,7 +1712,6 @@ static short kvm_s2_resolve_vma_size(const struct kvm_s2_fault_desc *s2fd,
>
>  struct kvm_s2_fault {
>         bool writable;
> -       bool topup_memcache;
>         bool mte_allowed;
>         bool is_vma_cacheable;
>         bool s2_force_noncacheable;
> @@ -1983,7 +1982,6 @@ static int user_mem_abort(const struct kvm_s2_fault_desc *s2fd)
>                 .logging_active = logging_active,
>                 .force_pte = logging_active,
>                 .prot = KVM_PGTABLE_PROT_R,
> -               .topup_memcache = !perm_fault || (logging_active && kvm_is_write_fault(s2fd->vcpu)),
>         };
>         void *memcache;
>         int ret;
> @@ -1994,9 +1992,11 @@ static int user_mem_abort(const struct kvm_s2_fault_desc *s2fd)
>          * only exception to this is when dirty logging is enabled at runtime
>          * and a write fault needs to collapse a block entry into a table.
>          */
> -       ret = prepare_mmu_memcache(s2fd->vcpu, fault.topup_memcache, &memcache);
> -       if (ret)
> -               return ret;
> +       if (!perm_fault || (logging_active && kvm_is_write_fault(s2fd->vcpu))) {
> +               ret = prepare_mmu_memcache(s2fd->vcpu, true, &memcache);
> +               if (ret)
> +                       return ret;
> +       }

Further up in user_mem_abort(), when memcache is declared it should be
initialized to NULL, since prepare_mmu_memcache() isn't called if this
evaluates to false.

With that fixed:
Reviewed-by: Fuad Tabba <tabba at google.com>

Cheers,
/fuad

>
>         /*
>          * Let's check if we will get back a huge fault->page backed by hugetlbfs, or
> --
> 2.47.3
>