tree 951f327c633328c72877d7bd6be8a53d5cd349f8
parent 8d404c4c246137531f94dfee352f350d59d0e5a7
author Christoffer Dall <christoffer.dall@linaro.org> 1514062428 +0100
committer Marc Zyngier <marc.zyngier@arm.com> 1521456797 +0000

KVM: arm64: Introduce framework for accessing deferred sysregs

We are about to defer saving and restoring some groups of system
registers to vcpu_put and vcpu_load on supported systems.  This means
that we need some infrastructure to access system registes which
supports either accessing the memory backing of the register or directly
accessing the system registers, depending on the state of the system
when we access the register.

We do this by defining read/write accessor functions, which can handle
both "immediate" and "deferrable" system registers.  Immediate registers
are always saved/restored in the world-switch path, but deferrable
registers are only saved/restored in vcpu_put/vcpu_load when supported
and sysregs_loaded_on_cpu will be set in that case.

Note that we don't use the deferred mechanism yet in this patch, but only
introduce infrastructure.  This is to improve convenience of review in
the subsequent patches where it is clear which registers become
deferred.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>