[PATCH v3 05/21] arm64: kvm: deal with kernel symbols outside of linear mapping

On Mon, Jan 11, 2016 at 02:18:58PM +0100, Ard Biesheuvel wrote:

KVM on arm64 uses a fixed offset between the linear mapping at EL1 and
the HYP mapping at EL2. Before we can move the kernel virtual mapping
out of the linear mapping, we have to make sure that references to kernel
symbols that are accessed via the HYP mapping are translated to their
linear equivalent.

To prevent inadvertent direct references from sneaking in later, change
the type of all extern declarations to HYP kernel symbols to the opaque
'struct kvm_ksym', which does not decay to a pointer type like char arrays
and function references. This is not bullet proof, but at least forces the
user to take the address explicitly rather than referencing it directly.

Signed-off-by: Ard Biesheuvel <redacted>

Cool feature!

So that one doesn't have to trawl git logs, it might be worth a comment
as to the purpose of struct kvm_ksym (and thus why we never need to
actually define it).

Either way:

Reviewed-by: Mark Rutland <mark.rutland@arm.com>

Mark.