Re: [RFC PATCH v3 14/19] KVM: x86: rename .set_apic_access_page_addr to reload_apic_access_page

Sean Christopherson
2022-05-19T16:55:33Z

On Wed, Apr 27, 2022, Maxim Levitsky wrote:
> This will be used on SVM to reload shadow page of the AVIC physid table
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index d2f73ce87a1e3..ad744ab99734c 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -9949,12 +9949,12 @@ void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
> kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
> }
>
> -static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
> +static void kvm_vcpu_reload_apic_pages(struct kvm_vcpu *vcpu)
> {
> if (!lapic_in_kernel(vcpu))
> return;
>
> - static_call_cond(kvm_x86_set_apic_access_page_addr)(vcpu);
> + static_call_cond(kvm_x86_reload_apic_pages)(vcpu);
> }
>
> void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu)
> @@ -10071,7 +10071,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> if (kvm_check_request(KVM_REQ_LOAD_EOI_EXITMAP, vcpu))
> vcpu_load_eoi_exitmap(vcpu);
> if (kvm_check_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu))
> - kvm_vcpu_reload_apic_access_page(vcpu);
> + kvm_vcpu_reload_apic_pages(vcpu);

My vote is to add a new request and new kvm_x86_ops hook instead of piggybacking
KVM_REQ_APIC_PAGE_RELOAD. The usage in kvm_arch_mmu_notifier_invalidate_range()
very subtlies relies on the memslot and vma being allocated/controlled by KVM.

The use in avic_physid_shadow_table_flush_memslot() is too similar in that it
also deals with memslot changes, but at the same time is _very_ different in that
it's dealing with user controlled memslots.