Re: [PATCH v3 2/2] KVM: x86: directly use kvm_make_request again

[Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>]

On 09/19/2014 12:38 AM, Liang Chen wrote:
> A one-line wrapper around kvm_make_request does not seem
> particularly useful. Replace kvm_mmu_flush_tlb() with
> kvm_make_request() again to free the namespace a bit.
> 
> Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
> ---
>  arch/x86/include/asm/kvm_host.h |  1 -
>  arch/x86/kvm/mmu.c              | 16 +++++-----------
>  arch/x86/kvm/vmx.c              |  2 +-
>  arch/x86/kvm/x86.c              | 11 ++++++++---
>  4 files changed, 14 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 7c492ed..77ade89 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -917,7 +917,6 @@ void kvm_inject_nmi(struct kvm_vcpu *vcpu);
> 
>  int fx_init(struct kvm_vcpu *vcpu);
> 
> -void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu);
>  void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
>  		       const u8 *new, int bytes);
>  int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn);
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index b41fd97..acc2d0c5 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -1749,7 +1749,7 @@ static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
>  		return 1;
>  	}
> 
> -	kvm_mmu_flush_tlb(vcpu);
> +	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
>  	return 0;
>  }
> 
> @@ -1802,7 +1802,7 @@ static void kvm_sync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
> 
>  	kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
>  	if (flush)
> -		kvm_mmu_flush_tlb(vcpu);
> +		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
>  }
> 
>  struct mmu_page_path {
> @@ -2536,7 +2536,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
>  	      true, host_writable)) {
>  		if (write_fault)
>  			*emulate = 1;
> -		kvm_mmu_flush_tlb(vcpu);
> +		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
>  	}
> 
>  	if (unlikely(is_mmio_spte(*sptep) && emulate))
> @@ -3450,12 +3450,6 @@ static void nonpaging_init_context(struct kvm_vcpu *vcpu,
>  	context->nx = false;
>  }
> 
> -void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
> -{
> -	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
> -}
> -EXPORT_SYMBOL_GPL(kvm_mmu_flush_tlb);
> -
>  void kvm_mmu_new_cr3(struct kvm_vcpu *vcpu)
>  {
>  	mmu_free_roots(vcpu);
> @@ -3961,7 +3955,7 @@ static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, bool zap_page,
>  	if (remote_flush)
>  		kvm_flush_remote_tlbs(vcpu->kvm);
>  	else if (local_flush)
> -		kvm_mmu_flush_tlb(vcpu);
> +		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
>  }
> 
>  static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
> @@ -4222,7 +4216,7 @@ EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
>  void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
>  {
>  	vcpu->arch.mmu.invlpg(vcpu, gva);
> -	kvm_mmu_flush_tlb(vcpu);
> +	kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
>  	++vcpu->stat.invlpg;
>  }
>  EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index bfe11cf..bb0a7ab 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -6617,7 +6617,7 @@ static int handle_invept(struct kvm_vcpu *vcpu)
>  	switch (type) {
>  	case VMX_EPT_EXTENT_GLOBAL:
>  		kvm_mmu_sync_roots(vcpu);
> -		kvm_mmu_flush_tlb(vcpu);
> +		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
>  		nested_vmx_succeed(vcpu);
>  		break;
>  	default:
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 9eb5458..fc3df50 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -726,7 +726,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
>  {
>  	if (cr3 == kvm_read_cr3(vcpu) && !pdptrs_changed(vcpu)) {
>  		kvm_mmu_sync_roots(vcpu);
> -		kvm_mmu_flush_tlb(vcpu);
> +		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
>  		return 0;
>  	}
> 
> @@ -5989,6 +5989,12 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
>  	kvm_apic_update_tmr(vcpu, tmr);
>  }
> 
> +static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
> +{
> +	++vcpu->stat.tlb_flush;
> +	kvm_x86_ops->tlb_flush(vcpu);
> +}
> +
>  /*
>   * Returns 1 to let __vcpu_run() continue the guest execution loop without
>   * exiting to the userspace.  Otherwise, the value will be returned to the
> @@ -6018,8 +6024,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
>  		if (kvm_check_request(KVM_REQ_MMU_SYNC, vcpu))
>  			kvm_mmu_sync_roots(vcpu);
>  		if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) {
> -			++vcpu->stat.tlb_flush;
> -			kvm_x86_ops->tlb_flush(vcpu);
> +			kvm_vcpu_flush_tlb(vcpu);

NACK!

Do not understand why you have to introduce a meaningful name
here - it's used just inner a function, which can not help to
improve a readability of the code at all.

What i suggested is renaming kvm_mmu_flush_tlb() since it's a
API used in multiple files - a good name helps developer to
know what it's doing and definitely easier typing.