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3b2c81d5fe
The ITS ABI infrastructure allows for some pretty lax code, where
the size of the data doesn't have to match the size of the entry,
potentially leading to a collection of interesting bugs.
Commit 7fe28d7e68f9 ("KVM: arm64: vgic-its: Add a data length check
in vgic_its_save_*") added some checks, but starts by implicitly
casting all writes to a 64bit value, hiding some of the issues.
Instead, introduce macros that will check the data type actually used
for dealing with the table entries. The macros are taking a symbolic
entry type that is used to fetch the size of the entry type for the
current ABI. This immediately catches a couple of low-impact gotchas
(zero values that are implicitly 32bit), easy enough to fix.
Given that we currently only have a single ABI, hardcode a couple of
BUILD_BUG_ON()s that will fire if we use anything but a 64bit quantity,
and some (currently unreachable) fallback code that may become useful
one day.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241117165757.247686-5-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>