Re: [PATCH 23/59] KVM: arm64: nv: Respect virtual HCR_EL2.TWX setting

Marc Zyngier
2019-07-03T14:18:22Z

On 25/06/2019 15:19, Julien Thierry wrote:
>
>
> On 06/21/2019 10:38 AM, Marc Zyngier wrote:
>> From: Jintack Lim <jintack.lim@linaro.org>
>>
>> Forward exceptions due to WFI or WFE instructions to the virtual EL2 if
>> they are not coming from the virtual EL2 and virtual HCR_EL2.TWX is set.
>>
>> Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>> arch/arm64/include/asm/kvm_nested.h | 2 ++
>> arch/arm64/kvm/Makefile | 1 +
>> arch/arm64/kvm/handle_exit.c | 13 +++++++++-
>> arch/arm64/kvm/nested.c | 39 +++++++++++++++++++++++++++++
>> 4 files changed, 54 insertions(+), 1 deletion(-)
>> create mode 100644 arch/arm64/kvm/nested.c
>>
>> diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
>> index 8a3d121a0b42..645e5e11b749 100644
>> --- a/arch/arm64/include/asm/kvm_nested.h
>> +++ b/arch/arm64/include/asm/kvm_nested.h
>> @@ -10,4 +10,6 @@ static inline bool nested_virt_in_use(const struct kvm_vcpu *vcpu)
>> test_bit(KVM_ARM_VCPU_NESTED_VIRT, vcpu->arch.features);
>> }
>>
>> +int handle_wfx_nested(struct kvm_vcpu *vcpu, bool is_wfe);
>> +
>> #endif /* __ARM64_KVM_NESTED_H */
>> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
>> index 9e450aea7db6..f11bd8b0d837 100644
>> --- a/arch/arm64/kvm/Makefile
>> +++ b/arch/arm64/kvm/Makefile
>> @@ -36,4 +36,5 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/irqchip.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arch_timer.o
>> kvm-$(CONFIG_KVM_ARM_PMU) += $(KVM)/arm/pmu.o
>>
>> +kvm-$(CONFIG_KVM_ARM_HOST) += nested.o
>> kvm-$(CONFIG_KVM_ARM_HOST) += emulate-nested.o
>> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
>> index e348c15c81bc..ddba212fd6ec 100644
>> --- a/arch/arm64/kvm/handle_exit.c
>> +++ b/arch/arm64/kvm/handle_exit.c
>> @@ -127,7 +127,18 @@ static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run)
>> */
>> static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
>> {
>> - if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
>> + bool is_wfe = !!(kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE);
>> +
>> + if (nested_virt_in_use(vcpu)) {
>> + int ret = handle_wfx_nested(vcpu, is_wfe);
>> +
>> + if (ret < 0 && ret != -EINVAL)
>> + return ret;
>> + else if (ret >= 0)
>> + return ret;
>
> I think you can simplify this:
>
> if (ret != -EINVAL)
> return ret;

Ah! Yes. ;-)

M.
--
Jazz is not dead. It just smells funny...