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| author | Christoffer Dall <christoffer.dall@linaro.org> | 2017-10-27 19:57:51 +0200 |
|---|---|---|
| committer | Christoffer Dall <christoffer.dall@linaro.org> | 2018-01-02 10:05:46 +0100 |
| commit | 61bbe38027334780964e4b2658f722ed0b3cb2f9 (patch) | |
| tree | 51acd9c382cbb311bf931a68552eeae3ae20e27f /arch | |
| parent | 4c60e360d6dfa4d9c3586b687f348eeb3fd675dd (diff) | |
| download | linux-rpi-61bbe38027334780964e4b2658f722ed0b3cb2f9.tar.gz linux-rpi-61bbe38027334780964e4b2658f722ed0b3cb2f9.tar.bz2 linux-rpi-61bbe38027334780964e4b2658f722ed0b3cb2f9.zip | |
KVM: arm/arm64: Avoid work when userspace iqchips are not used
We currently check if the VM has a userspace irqchip in several places
along the critical path, and if so, we do some work which is only
required for having an irqchip in userspace. This is unfortunate, as we
could avoid doing any work entirely, if we didn't have to support
irqchip in userspace.
Realizing the userspace irqchip on ARM is mostly a developer or hobby
feature, and is unlikely to be used in servers or other scenarios where
performance is a priority, we can use a refcounted static key to only
check the irqchip configuration when we have at least one VM that uses
an irqchip in userspace.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/include/asm/kvm_host.h | 2 | ||||
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 2 |
2 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index a9f7d3f47134..6394fb99da7f 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -48,6 +48,8 @@ KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1) +DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use); + u32 *kvm_vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num, u32 mode); int __attribute_const__ kvm_target_cpu(void); int kvm_reset_vcpu(struct kvm_vcpu *vcpu); diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index ea6cb5b24258..e7218cf7df2a 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -47,6 +47,8 @@ KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1) +DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use); + int __attribute_const__ kvm_target_cpu(void); int kvm_reset_vcpu(struct kvm_vcpu *vcpu); int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext); |