Re: [RFC PATCH v11 05/29] KVM: Convert KVM_ARCH_WANT_MMU_NOTIFIER to CONFIG_KVM_GENERIC_MMU_NOTIFIER
From: Sean Christopherson <seanjc@google.com>
Date: 2023-07-19 14:15:17
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kvm, kvm-riscv, kvmarm, linux-arm-kernel, linux-fsdevel, linux-mips, linux-mm, linux-riscv, linux-security-module, lkml
On Wed, Jul 19, 2023, Yuan Yao wrote:
On Tue, Jul 18, 2023 at 04:44:48PM -0700, Sean Christopherson wrote:quoted
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 90a0be261a5c..d2d3e083ec7f 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h@@ -255,7 +255,9 @@ bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); #endif -#ifdef KVM_ARCH_WANT_MMU_NOTIFIER +struct kvm_gfn_range;Not sure why a declaration here, it's defined for ARCHs which defined KVM_ARCH_WANT_MMU_NOTIFIER before.
The forward declaration exists to handle cases where CONFIG_KVM=n, specifically arch/powerpc/include/asm/kvm_ppc.h's declaration of hooks to forward calls to uarch modules: bool (*unmap_gfn_range)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*age_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*test_age_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); bool (*set_spte_gfn)(struct kvm *kvm, struct kvm_gfn_range *range); Prior to using a Kconfig, a forward declaration wasn't necessary because arch/powerpc/include/asm/kvm_host.h would #define KVM_ARCH_WANT_MMU_NOTIFIER even if CONFIG_KVM=n. Alternatively, kvm_ppc.h could declare the struct. I went this route mainly to avoid the possibility of someone encountering the same problem on a different architecture.