linux/arch/arm64/kvm/Kconfig
Marc Zyngier d241aac798 arm64: KVM: Yield CPU when vcpu executes a WFE
On an (even slightly) oversubscribed system, spinlocks are quickly
becoming a bottleneck, as some vcpus are spinning, waiting for a
lock to be released, while the vcpu holding the lock may not be
running at all.

The solution is to trap blocking WFEs and tell KVM that we're
now spinning. This ensures that other vpus will get a scheduling
boost, allowing the lock to be released more quickly. Also, using
CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT slightly improves the performance
when the VM is severely overcommited.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2013-10-29 18:25:25 +00:00

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#
# KVM configuration
#
source "virt/kvm/Kconfig"
menuconfig VIRTUALIZATION
bool "Virtualization"
---help---
Say Y here to get to see options for using your Linux host to run
other operating systems inside virtual machines (guests).
This option alone does not add any kernel code.
If you say N, all options in this submenu will be skipped and
disabled.
if VIRTUALIZATION
config KVM
bool "Kernel-based Virtual Machine (KVM) support"
select MMU_NOTIFIER
select PREEMPT_NOTIFIERS
select ANON_INODES
select HAVE_KVM_CPU_RELAX_INTERCEPT
select KVM_MMIO
select KVM_ARM_HOST
select KVM_ARM_VGIC
select KVM_ARM_TIMER
---help---
Support hosting virtualized guest machines.
If unsure, say N.
config KVM_ARM_HOST
bool
---help---
Provides host support for ARM processors.
config KVM_ARM_VGIC
bool
depends on KVM_ARM_HOST && OF
select HAVE_KVM_IRQCHIP
---help---
Adds support for a hardware assisted, in-kernel GIC emulation.
config KVM_ARM_TIMER
bool
depends on KVM_ARM_VGIC
---help---
Adds support for the Architected Timers in virtual machines.
endif # VIRTUALIZATION