Re: [PATCH v4 04/17] KVM: arm64: Add a heap allocator for the pKVM hyp

On Tue, Aug 18, 2026 at 03:22:55PM +0100, Fuad Tabba wrote:

Hi Vincent,

On Fri, 31 Jul 2026 at 15:36, 'Vincent Donnefort' via kernel-team
[off-list ref] wrote:
...

quoted

+static int hyp_allocator_destroy_chunk(struct hyp_allocator *allocator,
+                                      struct chunk_hdr *prev,
+                                      struct chunk_hdr *chunk)
+{
+       struct chunk_hdr *next;
+
+       next = prev ? chunk_get_next(chunk) : NULL;
+       if (!hyp_allocator_can_destroy_chunk(allocator, prev, next, chunk))
+               return -EINVAL;
+
+       /* Last chunk in the allocator */
+       if (!prev) {
+               allocator->first_unmapped = chunk_unmapped(chunk);
+               allocator->head = allocator->tail = NULL;
+               return 0;
+       }

hyp_allocator_destroy_chunk() has only two callers, both in
hyp_allocator_free(), and both pass a non-NULL prev. So this !prev
branch cannot be reached, and nor can the matching "if (!prev) return
true;" in hyp_allocator_can_destroy_chunk() or the false arm of "next
= prev ? chunk_get_next(chunk) : NULL".

The empty-allocator reset it looks like it is handling already happens
in hyp_allocator_reclaim_chunk(), in the addr == allocator->start
case. Could these be dropped?

Ha yes, correct, that's leftover of the Android version. I can then remove that
allocator argument in hyp_allocator_can_destroy_chunk().

With that:

Reviewed-by: Fuad Tabba <fuad.tabba@linux.dev>

Cheers,
/fuad

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