[PATCH] KVM: arm64: Enforce dependency on an ARMv8.4-aware toolchain

[Marc Zyngier]

With the NV support of TLBI-range operations, KVM makes use of
instructions that are only supported by binutils versions >= 2.30.

This breaks the build for very old toolchains.

Make KVM support conditional on having ARMv8.4 support in the
assembler, side-stepping the issue.

Fixes: 5d476ca57d7d ("KVM: arm64: nv: Add handling of range-based TLBI operations")
Reported-by: Viresh Kumar <viresh.kumar at linaro.org>
Suggested-by: Arnd Bergmann <arnd at linaro.org>
Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kvm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 58f09370d17e..8304eb342be9 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -19,6 +19,7 @@ if VIRTUALIZATION
 
 menuconfig KVM
 	bool "Kernel-based Virtual Machine (KVM) support"
+	depends on AS_HAS_ARMV8_4
 	select KVM_COMMON
 	select KVM_GENERIC_HARDWARE_ENABLING
 	select KVM_GENERIC_MMU_NOTIFIER
-- 
2.39.2