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

From: Xiao Guangrong
Date: Fri Sep 19 2014 - 02:12:37 EST


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@xxxxxxxxx>
> ---
> 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.



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