Revert "KVM: arm64: vgic-its: Don't save collections the table cannot hold"

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This reverts commit 9b10fb74e4.

Freeing the collections when GITS_BASER<coll> changes removes the state
this check rejected: vgic_its_cmd_handle_mapi(),
vgic_its_cmd_handle_mapc() and vgic_its_restore_cte() all validate the
ID against the current table before allocating, and the table can no
longer change under the list. What remains is a collection whose entry
is not backed by a memslot, which the write fails on anyway, so the
check costs a save userspace should be able to issue reliably and buys
nothing.

The reverted commit credited the check with bounding the walk as well.
It stays bounded without it: collection IDs are unique and each is below
the table's capacity, so the list cannot be longer than the table.

Suggested-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/all/87ecg9owwa.wl-maz@kernel.org/
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://patch.msgid.link/20260821064445.615838-3-fuad.tabba@linux.dev
Signed-off-by: Oliver Upton <oupton@kernel.org>

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Fuad Tabba 2026-08-21 07:44:43 +01:00 • committed by Oliver Upton

parent 8cd92f77ae

commit 30908e7272

1 changed files with 0 additions and 3 deletions

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arch/arm64/kvm/vgic/vgic-its.c

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