[PATCH v2 2/2] arm: KVM: keep arm vfp/simd exit handling consistent with arm64
Marc Zyngier
marc.zyngier at arm.com
Fri Jun 19 06:50:33 PDT 2015
On 19/06/15 00:49, Mario Smarduch wrote:
> On 06/18/2015 10:27 AM, Marc Zyngier wrote:
>> On 16/06/15 22:50, Mario Smarduch wrote:
>>> After enhancing arm64 FP/SIMD exit handling, FP/SIMD exit branch is moved
>>> to guest trap handling. This keeps exiting handling flow between both
>>> architectures consistent.
>>>
>>> Signed-off-by: Mario Smarduch <m.smarduch at samsung.com>
>>> ---
>>> arch/arm/kvm/interrupts.S | 12 +++++++-----
>>> 1 file changed, 7 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
>>> index 79caf79..fca2c56 100644
>>> --- a/arch/arm/kvm/interrupts.S
>>> +++ b/arch/arm/kvm/interrupts.S
>>> @@ -363,10 +363,6 @@ hyp_hvc:
>>> @ Check syndrome register
>>> mrc p15, 4, r1, c5, c2, 0 @ HSR
>>> lsr r0, r1, #HSR_EC_SHIFT
>>> -#ifdef CONFIG_VFPv3
>>> - cmp r0, #HSR_EC_CP_0_13
>>> - beq switch_to_guest_vfp
>>> -#endif
>>> cmp r0, #HSR_EC_HVC
>>> bne guest_trap @ Not HVC instr.
>>>
>>> @@ -406,6 +402,12 @@ THUMB( orr lr, #1)
>>> 1: eret
>>>
>>> guest_trap:
>>> +#ifdef CONFIG_VFPv3
>>> + /* Guest accessed VFP/SIMD registers, save host, restore Guest */
>>> + cmp r0, #HSR_EC_CP_0_13
>>> + beq switch_to_guest_fpsimd
>>> +#endif
>>> +
>>> load_vcpu @ Load VCPU pointer to r0
>>> str r1, [vcpu, #VCPU_HSR]
>>>
>>> @@ -478,7 +480,7 @@ guest_trap:
>>> * inject an undefined exception to the guest.
>>> */
>>> #ifdef CONFIG_VFPv3
>>> -switch_to_guest_vfp:
>>> +switch_to_guest_fpsimd:
>>
>> Ah, I think I managed to confuse you in my previous comment.
>> On ARMv7, we call the floating point stuff VFP.
>> On ARMv8, we call it FP/SIMD.
>
> Ah I see, I'll update.
>>
>> Not very consistent, I know...
>>
>>> load_vcpu @ Load VCPU pointer to r0
>
> How about move it here - then it does not stick out like
> before.
>
> guest_trap:
> load_vcpu @ Load VCPU pointer to r0
> str r1, [vcpu, #VCPU_HSR]
>
> @ Check if we need the fault information
> lsr r1, r1, #HSR_EC_SHIFT
> #ifdef CONFIG_VFPv3
> /* Guest accessed VFP/SIMD registers, save host, restore Guest */
> cmp r1, #HSR_EC_CP_0_13
> beq switch_to_guest_vfp
> #endif
That would work.
> Regarding "host_switch_to_hyp:" it has no reference but appears
> like a clean separator, that's on purpose?
Not really. It looks like a leftover from the original HYP calling
method that we used to have, before the code got merged.
You could replace it by a simple comment saying that from this point on,
we're dealing with a HVC call from the host.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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