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

From: [email-masked] (Marc Zyngier)
Date: Thu, 03 Dec 2015 19:24:06 +0000

On 03/12/15 19:21, Mario Smarduch wrote:
> 
> 
> 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?

But that's what should actually be preserved, no? At the moment, you
maintain some side state to reflect what the trapping state is. You
might as well keep it around all the time.

Thanks,

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