KVM: arm64/sve: Explain validity checks in set_sve_vls()
authorDave Martin <Dave.Martin@arm.com>
Thu, 11 Apr 2019 16:23:00 +0000 (17:23 +0100)
committerMarc Zyngier <marc.zyngier@arm.com>
Thu, 18 Apr 2019 16:14:02 +0000 (17:14 +0100)
commitecfb6ed4f66e68129c3ab675c68cb6578c28ef9b
treec74cce8fb8468ec7514bf0f67521b83435842fa1
parent4bd774e57b29f5bbf296d1daf69cc761e1e75fa8
KVM: arm64/sve: Explain validity checks in set_sve_vls()

Correct virtualization of SVE relies for correctness on code in
set_sve_vls() that verifies consistency between the set of vector
lengths requested by userspace and the set of vector lengths
available on the host.

However, the purpose of this code is not obvious, and not likely to
be apparent at all to people who do not have detailed knowledge of
the SVE system-level architecture.

This patch adds a suitable comment to explain what these checks are
for.

No functional change.

Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
arch/arm64/kvm/guest.c