From: Juergen Gross Date: Fri, 8 Nov 2024 16:14:16 +0000 (+0100) Subject: KVM/x86: add comment to kvm_mmu_do_page_fault() X-Git-Tag: v6.14-rc1~94^2~7^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2d5faa6a8402435d6332e8e8f3c3f18cca382d83;p=thirdparty%2Fkernel%2Flinux.git KVM/x86: add comment to kvm_mmu_do_page_fault() On a first glance it isn't obvious why calling kvm_tdp_page_fault() in kvm_mmu_do_page_fault() is special cased, as the general case of using an indirect case would result in calling of kvm_tdp_page_fault() anyway. Add a comment to explain the reason. Signed-off-by: Juergen Gross Link: https://lore.kernel.org/r/20241108161416.28552-1-jgross@suse.com Signed-off-by: Sean Christopherson --- diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index b00abbe3f6cfa..72de71f4bc8be 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -321,6 +321,10 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn); } + /* + * With retpoline being active an indirect call is rather expensive, + * so do a direct call in the most common case. + */ if (IS_ENABLED(CONFIG_MITIGATION_RETPOLINE) && fault.is_tdp) r = kvm_tdp_page_fault(vcpu, &fault); else