Re: [RFC PATCH v11 05/29] KVM: Convert KVM_ARCH_WANT_MMU_NOTIFIER to CONFIG_KVM_GENERIC_MMU_NOTIFIER

[Yuan Yao <yuan.yao@linux.intel.com>]

On Tue, Jul 18, 2023 at 04:44:48PM -0700, Sean Christopherson wrote:
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>  arch/arm64/include/asm/kvm_host.h   |  2 --
>  arch/arm64/kvm/Kconfig              |  2 +-
>  arch/mips/include/asm/kvm_host.h    |  2 --
>  arch/mips/kvm/Kconfig               |  2 +-
>  arch/powerpc/include/asm/kvm_host.h |  2 --
>  arch/powerpc/kvm/Kconfig            |  8 ++++----
>  arch/powerpc/kvm/powerpc.c          |  4 +---
>  arch/riscv/include/asm/kvm_host.h   |  2 --
>  arch/riscv/kvm/Kconfig              |  2 +-
>  arch/x86/include/asm/kvm_host.h     |  2 --
>  arch/x86/kvm/Kconfig                |  2 +-
>  include/linux/kvm_host.h            |  8 +++++---
>  virt/kvm/Kconfig                    |  4 ++++
>  virt/kvm/kvm_main.c                 | 10 +++++-----
>  14 files changed, 23 insertions(+), 29 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 8b6096753740..50d89d400bf1 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -912,8 +912,6 @@ int __kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu,
>  int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
>  			      struct kvm_vcpu_events *events);
>
> -#define KVM_ARCH_WANT_MMU_NOTIFIER
> -
>  void kvm_arm_halt_guest(struct kvm *kvm);
>  void kvm_arm_resume_guest(struct kvm *kvm);
>
> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
> index f531da6b362e..a650b46f4f2f 100644
> --- a/arch/arm64/kvm/Kconfig
> +++ b/arch/arm64/kvm/Kconfig
> @@ -22,7 +22,7 @@ menuconfig KVM
>  	bool "Kernel-based Virtual Machine (KVM) support"
>  	depends on HAVE_KVM
>  	select KVM_GENERIC_HARDWARE_ENABLING
> -	select MMU_NOTIFIER
> +	select KVM_GENERIC_MMU_NOTIFIER
>  	select PREEMPT_NOTIFIERS
>  	select HAVE_KVM_CPU_RELAX_INTERCEPT
>  	select HAVE_KVM_ARCH_TLB_FLUSH_ALL
> diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
> index 04cedf9f8811..22a41d941bf3 100644
> --- a/arch/mips/include/asm/kvm_host.h
> +++ b/arch/mips/include/asm/kvm_host.h
> @@ -810,8 +810,6 @@ int kvm_mips_mkclean_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn);
>  pgd_t *kvm_pgd_alloc(void);
>  void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
>
> -#define KVM_ARCH_WANT_MMU_NOTIFIER
> -
>  /* Emulation */
>  enum emulation_result update_pc(struct kvm_vcpu *vcpu, u32 cause);
>  int kvm_get_badinstr(u32 *opc, struct kvm_vcpu *vcpu, u32 *out);
> diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
> index a8cdba75f98d..c04987d2ed2e 100644
> --- a/arch/mips/kvm/Kconfig
> +++ b/arch/mips/kvm/Kconfig
> @@ -25,7 +25,7 @@ config KVM
>  	select HAVE_KVM_EVENTFD
>  	select HAVE_KVM_VCPU_ASYNC_IOCTL
>  	select KVM_MMIO
> -	select MMU_NOTIFIER
> +	select KVM_GENERIC_MMU_NOTIFIER
>  	select INTERVAL_TREE
>  	select KVM_GENERIC_HARDWARE_ENABLING
>  	help
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index 14ee0dece853..4b5c3f2acf78 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -62,8 +62,6 @@
>
>  #include <linux/mmu_notifier.h>
>
> -#define KVM_ARCH_WANT_MMU_NOTIFIER
> -
>  #define HPTEG_CACHE_NUM			(1 << 15)
>  #define HPTEG_HASH_BITS_PTE		13
>  #define HPTEG_HASH_BITS_PTE_LONG	12
> diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
> index 902611954200..b33358ee6424 100644
> --- a/arch/powerpc/kvm/Kconfig
> +++ b/arch/powerpc/kvm/Kconfig
> @@ -42,7 +42,7 @@ config KVM_BOOK3S_64_HANDLER
>  config KVM_BOOK3S_PR_POSSIBLE
>  	bool
>  	select KVM_MMIO
> -	select MMU_NOTIFIER
> +	select KVM_GENERIC_MMU_NOTIFIER
>
>  config KVM_BOOK3S_HV_POSSIBLE
>  	bool
> @@ -85,7 +85,7 @@ config KVM_BOOK3S_64_HV
>  	tristate "KVM for POWER7 and later using hypervisor mode in host"
>  	depends on KVM_BOOK3S_64 && PPC_POWERNV
>  	select KVM_BOOK3S_HV_POSSIBLE
> -	select MMU_NOTIFIER
> +	select KVM_GENERIC_MMU_NOTIFIER
>  	select CMA
>  	help
>  	  Support running unmodified book3s_64 guest kernels in
> @@ -194,7 +194,7 @@ config KVM_E500V2
>  	depends on !CONTEXT_TRACKING_USER
>  	select KVM
>  	select KVM_MMIO
> -	select MMU_NOTIFIER
> +	select KVM_GENERIC_MMU_NOTIFIER
>  	help
>  	  Support running unmodified E500 guest kernels in virtual machines on
>  	  E500v2 host processors.
> @@ -211,7 +211,7 @@ config KVM_E500MC
>  	select KVM
>  	select KVM_MMIO
>  	select KVM_BOOKE_HV
> -	select MMU_NOTIFIER
> +	select KVM_GENERIC_MMU_NOTIFIER
>  	help
>  	  Support running unmodified E500MC/E5500/E6500 guest kernels in
>  	  virtual machines on E500MC/E5500/E6500 host processors.
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 5cf9e5e3112a..f97fbac7eac9 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -635,9 +635,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>  #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
>  		r = hv_enabled;
>  #else
> -#ifndef KVM_ARCH_WANT_MMU_NOTIFIER
> -		BUILD_BUG();
> -#endif
> +		BUILD_BUG_ON(!IS_ENABLED(CONFIG_KVM_GENERIC_MMU_NOTIFIER));
>  		r = 1;
>  #endif
>  		break;
> diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
> index 2d8ee53b66c7..6ddaf0b9278c 100644
> --- a/arch/riscv/include/asm/kvm_host.h
> +++ b/arch/riscv/include/asm/kvm_host.h
> @@ -249,8 +249,6 @@ struct kvm_vcpu_arch {
>  static inline void kvm_arch_sync_events(struct kvm *kvm) {}
>  static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
>
> -#define KVM_ARCH_WANT_MMU_NOTIFIER
> -
>  #define KVM_RISCV_GSTAGE_TLB_MIN_ORDER		12
>
>  void kvm_riscv_local_hfence_gvma_vmid_gpa(unsigned long vmid,
> diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
> index dfc237d7875b..ae2e05f050ec 100644
> --- a/arch/riscv/kvm/Kconfig
> +++ b/arch/riscv/kvm/Kconfig
> @@ -30,7 +30,7 @@ config KVM
>  	select KVM_GENERIC_HARDWARE_ENABLING
>  	select KVM_MMIO
>  	select KVM_XFER_TO_GUEST_WORK
> -	select MMU_NOTIFIER
> +	select KVM_GENERIC_MMU_NOTIFIER
>  	select PREEMPT_NOTIFIERS
>  	help
>  	  Support hosting virtualized guest machines.
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 28bd38303d70..f9a927296d85 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -2110,8 +2110,6 @@ enum {
>  # define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, 0)
>  #endif
>
> -#define KVM_ARCH_WANT_MMU_NOTIFIER
> -
>  int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v);
>  int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu);
>  int kvm_cpu_has_extint(struct kvm_vcpu *v);
> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
> index 89ca7f4c1464..a7eb2bdbfb18 100644
> --- a/arch/x86/kvm/Kconfig
> +++ b/arch/x86/kvm/Kconfig
> @@ -24,7 +24,7 @@ config KVM
>  	depends on HIGH_RES_TIMERS
>  	depends on X86_LOCAL_APIC
>  	select PREEMPT_NOTIFIERS
> -	select MMU_NOTIFIER
> +	select KVM_GENERIC_MMU_NOTIFIER
>  	select HAVE_KVM_IRQCHIP
>  	select HAVE_KVM_PFNCACHE
>  	select HAVE_KVM_IRQFD
> 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.

> +
> +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
>  struct kvm_gfn_range {
>  	struct kvm_memory_slot *slot;
>  	gfn_t start;
> @@ -784,7 +786,7 @@ struct kvm {
>  	struct hlist_head irq_ack_notifier_list;
>  #endif
>
> -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
> +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
>  	struct mmu_notifier mmu_notifier;
>  	unsigned long mmu_invalidate_seq;
>  	long mmu_invalidate_in_progress;
> @@ -1916,7 +1918,7 @@ extern const struct _kvm_stats_desc kvm_vm_stats_desc[];
>  extern const struct kvm_stats_header kvm_vcpu_stats_header;
>  extern const struct _kvm_stats_desc kvm_vcpu_stats_desc[];
>
> -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
> +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
>  static inline int mmu_invalidate_retry(struct kvm *kvm, unsigned long mmu_seq)
>  {
>  	if (unlikely(kvm->mmu_invalidate_in_progress))
> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
> index b74916de5183..2fa11bd26cfc 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -95,3 +95,7 @@ config HAVE_KVM_PM_NOTIFIER
>
>  config KVM_GENERIC_HARDWARE_ENABLING
>         bool
> +
> +config KVM_GENERIC_MMU_NOTIFIER
> +       select MMU_NOTIFIER
> +       bool
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 8101b11a13ba..53346bc2902a 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -510,7 +510,7 @@ void kvm_destroy_vcpus(struct kvm *kvm)
>  }
>  EXPORT_SYMBOL_GPL(kvm_destroy_vcpus);
>
> -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
> +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
>  static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
>  {
>  	return container_of(mn, struct kvm, mmu_notifier);
> @@ -938,14 +938,14 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
>  	return mmu_notifier_register(&kvm->mmu_notifier, current->mm);
>  }
>
> -#else  /* !(CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER) */
> +#else  /* !CONFIG_KVM_GENERIC_MMU_NOTIFIER */
>
>  static int kvm_init_mmu_notifier(struct kvm *kvm)
>  {
>  	return 0;
>  }
>
> -#endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
> +#endif /* CONFIG_KVM_GENERIC_MMU_NOTIFIER */
>
>  #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
>  static int kvm_pm_notifier_call(struct notifier_block *bl,
> @@ -1265,7 +1265,7 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
>  out_err_no_debugfs:
>  	kvm_coalesced_mmio_free(kvm);
>  out_no_coalesced_mmio:
> -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
> +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
>  	if (kvm->mmu_notifier.ops)
>  		mmu_notifier_unregister(&kvm->mmu_notifier, current->mm);
>  #endif
> @@ -1325,7 +1325,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
>  		kvm->buses[i] = NULL;
>  	}
>  	kvm_coalesced_mmio_free(kvm);
> -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
> +#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
>  	mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
>  	/*
>  	 * At this point, pending calls to invalidate_range_start()
> --
> 2.41.0.255.g8b1d071c50-goog
>