Subject: [PATCH v2 1/2] KVM/arm: add hooks for armv7 fp/simd lazy switch support

From: [email-masked] (Mario Smarduch)
Date: Mon, 19 Oct 2015 16:16:53 -0700

On 10/19/2015 1:53 AM, Christoffer Dall wrote:
> On Sat, Sep 26, 2015 at 04:43:28PM -0700, Mario Smarduch wrote:
>> This patch adds vcpu fields to track lazy state, save host FPEXC, and 
>> offsets to fields.
>>
>> Signed-off-by: Mario Smarduch <[email-masked]>
>> ---
>>  arch/arm/include/asm/kvm_host.h | 6 ++++++
>>  arch/arm/kernel/asm-offsets.c   | 2 ++
>>  2 files changed, 8 insertions(+)
>>
>> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
>> index dcba0fa..194a8ef 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -111,6 +111,12 @@ struct kvm_vcpu_arch {
>>  	/* Interrupt related fields */
>>  	u32 irq_lines;		/* IRQ and FIQ levels */
>>  
>> +	/* Track fp/simd lazy switch state */
>> +	u32 vfp_lazy;
> 
> so is this a flags field or basically a boolean?  If the latter, what is
> does it mean when the field is true vs. false?
Yes it's a bool will update, and clarify comments.
> 
>> +
>> +	/* Save host FPEXC register to restore on vcpu put */
>> +	u32 saved_fpexc;
> 
> is this only the host's state?  If so, why not name it host_fpexc?
That's right itis host state, will change.
> 
> Thanks,
> -Christoffer
> 
>> +
>>  	/* Exception Information */
>>  	struct kvm_vcpu_fault_info fault;
>>  
>> diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
>> index 871b826..e1c3a41 100644
>> --- a/arch/arm/kernel/asm-offsets.c
>> +++ b/arch/arm/kernel/asm-offsets.c
>> @@ -186,6 +186,8 @@ int main(void)
>>    DEFINE(VCPU_CPSR,		offsetof(struct kvm_vcpu, arch.regs.usr_regs.ARM_cpsr));
>>    DEFINE(VCPU_HCR,		offsetof(struct kvm_vcpu, arch.hcr));
>>    DEFINE(VCPU_IRQ_LINES,	offsetof(struct kvm_vcpu, arch.irq_lines));
>> +  DEFINE(VCPU_VFP_LAZY,		offsetof(struct kvm_vcpu, arch.vfp_lazy));
>> +  DEFINE(VCPU_VFP_FPEXC,	offsetof(struct kvm_vcpu, arch.saved_fpexc));
>>    DEFINE(VCPU_HSR,		offsetof(struct kvm_vcpu, arch.fault.hsr));
>>    DEFINE(VCPU_HxFAR,		offsetof(struct kvm_vcpu, arch.fault.hxfar));
>>    DEFINE(VCPU_HPFAR,		offsetof(struct kvm_vcpu, arch.fault.hpfar));
>> -- 
>> 1.9.1
>>