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SubjectRe: [PATCH v1 2/2] LoongArch: KVM: Add lasx support
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在 2023/11/21 下午7:55, Huacai Chen 写道:
> On Tue, Nov 21, 2023 at 5:59 PM zhaotianrui <zhaotianrui@loongson.cn> wrote:
>>
>> 在 2023/11/16 下午3:19, WANG Xuerui 写道:
>>> On 11/15/23 17:19, Tianrui Zhao wrote:
>>>> This patch adds LASX support for LoongArch KVM. The LASX means
>>>> LoongArch 256-bits vector instruction.
>>>> There will be LASX exception in KVM when guest use the LASX
>>>> instruction. KVM will enable LASX and restore the vector
>>>> registers for guest then return to guest to continue running.
>>>>
>>>> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
>>>> ---
>>>> arch/loongarch/include/asm/kvm_host.h | 6 ++++
>>>> arch/loongarch/include/asm/kvm_vcpu.h | 10 +++++++
>>>> arch/loongarch/kernel/fpu.S | 1 +
>>>> arch/loongarch/kvm/exit.c | 18 +++++++++++
>>>> arch/loongarch/kvm/switch.S | 16 ++++++++++
>>>> arch/loongarch/kvm/trace.h | 4 ++-
>>>> arch/loongarch/kvm/vcpu.c | 43 ++++++++++++++++++++++++++-
>>>> 7 files changed, 96 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/arch/loongarch/include/asm/kvm_host.h
>>>> b/arch/loongarch/include/asm/kvm_host.h
>>>> index 6c65c25169..4c05b5eca0 100644
>>>> --- a/arch/loongarch/include/asm/kvm_host.h
>>>> +++ b/arch/loongarch/include/asm/kvm_host.h
>>>> @@ -95,6 +95,7 @@ enum emulation_result {
>>>> #define KVM_LARCH_SWCSR_LATEST (0x1 << 1)
>>>> #define KVM_LARCH_HWCSR_USABLE (0x1 << 2)
>>>> #define KVM_LARCH_LSX (0x1 << 3)
>>>> +#define KVM_LARCH_LASX (0x1 << 4)
>>>> struct kvm_vcpu_arch {
>>>> /*
>>>> @@ -181,6 +182,11 @@ static inline bool kvm_guest_has_lsx(struct
>>>> kvm_vcpu_arch *arch)
>>>> return arch->cpucfg[2] & CPUCFG2_LSX;
>>>> }
>>>> +static inline bool kvm_guest_has_lasx(struct kvm_vcpu_arch *arch)
>>>> +{
>>>> + return arch->cpucfg[2] & CPUCFG2_LASX;
>>>> +}
>>>> +
>>>> /* Debug: dump vcpu state */
>>>> int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
>>>> diff --git a/arch/loongarch/include/asm/kvm_vcpu.h
>>>> b/arch/loongarch/include/asm/kvm_vcpu.h
>>>> index c629771e12..4f87f16018 100644
>>>> --- a/arch/loongarch/include/asm/kvm_vcpu.h
>>>> +++ b/arch/loongarch/include/asm/kvm_vcpu.h
>>>> @@ -67,6 +67,16 @@ static inline void kvm_restore_lsx(struct
>>>> loongarch_fpu *fpu) { }
>>>> static inline void kvm_restore_lsx_upper(struct loongarch_fpu *fpu)
>>>> { }
>>>> #endif
>>>> +#ifdef CONFIG_CPU_HAS_LASX
>>>> +void kvm_own_lasx(struct kvm_vcpu *vcpu);
>>>> +void kvm_save_lasx(struct loongarch_fpu *fpu);
>>>> +void kvm_restore_lasx(struct loongarch_fpu *fpu);
>>>> +#else
>>>> +static inline void kvm_own_lasx(struct kvm_vcpu *vcpu) { }
>>>> +static inline void kvm_save_lasx(struct loongarch_fpu *fpu) { }
>>>> +static inline void kvm_restore_lasx(struct loongarch_fpu *fpu) { }
>>>> +#endif
>>>> +
>>>> void kvm_acquire_timer(struct kvm_vcpu *vcpu);
>>>> void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz);
>>>> void kvm_reset_timer(struct kvm_vcpu *vcpu);
>>>> diff --git a/arch/loongarch/kernel/fpu.S b/arch/loongarch/kernel/fpu.S
>>>> index d53ab10f46..f4524fe866 100644
>>>> --- a/arch/loongarch/kernel/fpu.S
>>>> +++ b/arch/loongarch/kernel/fpu.S
>>>> @@ -384,6 +384,7 @@ SYM_FUNC_START(_restore_lasx_upper)
>>>> lasx_restore_all_upper a0 t0 t1
>>>> jr ra
>>>> SYM_FUNC_END(_restore_lasx_upper)
>>>> +EXPORT_SYMBOL(_restore_lasx_upper)
>>> Why the added export? It doesn't seem necessary, given the previous
>>> patch doesn't have a similar export added for _restore_lsx_upper. (Or
>>> if it's truly needed it should probably become EXPORT_SYMBOL_GPL.)
>> It is needed to be exported, as it is called by kvm_own_lasx. However
>> the "_restore_lsx_upper" is not used in kvm.
> To keep consistency it is better to export both.
>
> Huacai
Thanks, I will export both functions.

Tianrui Zhao
>
>> Thanks
>> Tianrui Zhao
>>

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