Subject: [PATCH v4 1/3] KVM/arm/arm64: add hooks for armv7 fp/simd lazy switch support

From: [email-masked] (Mario Smarduch)
Date: Thu, 03 Dec 2015 11:21:23 -0800

On 12/3/2015 7:46 AM, Marc Zyngier wrote:
> On 14/11/15 22:12, 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 3df1e97..f1bf551 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -107,6 +107,12 @@ struct kvm_vcpu_arch {
>>  	/* Interrupt related fields */
>>  	u32 irq_lines;		/* IRQ and FIQ levels */
>>  
>> +	/* fp/simd dirty flag true if guest accessed register file */
>> +	bool    vfp_dirty;
> 
> I think we do not need this bool, because it is already represented by
> the state of the trapping bits.

The trapping bit state is lost on exit since they're cleared, no?

> 
>> +
>> +	/* Save host FPEXC register to later restore on vcpu put */
>> +	u32	host_fpexc;
>> +
>>  	/* 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..9f79712 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_DIRTY,	offsetof(struct kvm_vcpu, arch.vfp_dirty));
>> +  DEFINE(VCPU_VFP_HOST_FPEXC,	offsetof(struct kvm_vcpu, arch.host_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));
>>
> 
> Thanks,
> 
> 	M.
>