[PATCH v3 1/2] arm64: Add hypervisor safe helper for checking constant capabilities

On Tue, Nov 08, 2016 at 01:56:20PM +0000, Suzuki K Poulose wrote:

The hypervisor may not have full access to the kernel data structures
and hence cannot safely use cpus_have_cap() helper for checking the
system capability. Add a safe helper for hypervisors to check a constant
system capability, which *doesn't* fall back to checking the bitmap
maintained by the kernel. With this, make the cpus_have_cap() only
check the bitmask and force constant cap checks to use the new API
for quicker checks.

Cc: Robert Ritcher <redacted>
Cc: Tirumalesh Chalamarla <redacted>
Cc: Marc Zyngier <redacted>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <redacted>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arch/arm64/include/asm/cpufeature.h | 19 ++++++++++++-------
 arch/arm64/kernel/cpufeature.c      |  2 +-
 arch/arm64/kernel/process.c         |  2 +-
 drivers/irqchip/irq-gic-v3.c        | 13 +------------

It might be worth having the GIC changes as a separate patch, but either
way:

Reviewed-by: Will Deacon <redacted>

Will