From 441f7bfa99fe2b8a7e504aa72047e20579e88a5d Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 30 Nov 2022 23:09:33 +0000 Subject: KVM: Opt out of generic hardware enabling on s390 and PPC Allow architectures to opt out of the generic hardware enabling logic, and opt out on both s390 and PPC, which don't need to manually enable virtualization as it's always on (when available). In addition to letting s390 and PPC drop a bit of dead code, this will hopefully also allow ARM to clean up its related code, e.g. ARM has its own per-CPU flag to track which CPUs have enable hardware due to the need to keep hardware enabled indefinitely when pKVM is enabled. Signed-off-by: Sean Christopherson Acked-by: Anup Patel Message-Id: <20221130230934.1014142-50-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/arm64/kvm/Kconfig | 1 + arch/mips/kvm/Kconfig | 1 + arch/powerpc/include/asm/kvm_host.h | 1 - arch/powerpc/kvm/powerpc.c | 5 ----- arch/riscv/kvm/Kconfig | 1 + arch/s390/include/asm/kvm_host.h | 1 - arch/s390/kvm/kvm-s390.c | 6 ------ arch/x86/kvm/Kconfig | 1 + include/linux/kvm_host.h | 4 ++++ virt/kvm/Kconfig | 3 +++ virt/kvm/kvm_main.c | 30 ++++++++++++++++++++++++------ 11 files changed, 35 insertions(+), 19 deletions(-) diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 05da3c8f7e88..ca6eadeb7d1a 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -21,6 +21,7 @@ if VIRTUALIZATION menuconfig KVM bool "Kernel-based Virtual Machine (KVM) support" depends on HAVE_KVM + select KVM_GENERIC_HARDWARE_ENABLING select MMU_NOTIFIER select PREEMPT_NOTIFIERS select HAVE_KVM_CPU_RELAX_INTERCEPT diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig index 91d197bee9c0..29e51649203b 100644 --- a/arch/mips/kvm/Kconfig +++ b/arch/mips/kvm/Kconfig @@ -28,6 +28,7 @@ config KVM select MMU_NOTIFIER select SRCU select INTERVAL_TREE + select KVM_GENERIC_HARDWARE_ENABLING help Support for hosting Guest kernels. diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 0a80e80c7b9e..959f566a455c 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -876,7 +876,6 @@ struct kvm_vcpu_arch { #define __KVM_HAVE_ARCH_WQP #define __KVM_HAVE_CREATE_DEVICE -static inline void kvm_arch_hardware_disable(void) {} static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen) {} static inline void kvm_arch_flush_shadow_all(struct kvm *kvm) {} diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index f5b4ff6bfc89..4c5405fc5538 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -435,11 +435,6 @@ int kvmppc_ld(struct kvm_vcpu *vcpu, ulong *eaddr, int size, void *ptr, } EXPORT_SYMBOL_GPL(kvmppc_ld); -int kvm_arch_hardware_enable(void) -{ - return 0; -} - int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) { struct kvmppc_ops *kvm_ops = NULL; diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig index f36a737d5f96..d5a658a047a7 100644 --- a/arch/riscv/kvm/Kconfig +++ b/arch/riscv/kvm/Kconfig @@ -20,6 +20,7 @@ if VIRTUALIZATION config KVM tristate "Kernel-based Virtual Machine (KVM) support (EXPERIMENTAL)" depends on RISCV_SBI && MMU + select KVM_GENERIC_HARDWARE_ENABLING select MMU_NOTIFIER select PREEMPT_NOTIFIERS select KVM_MMIO diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index d67ce719d16a..2bbc3d54959d 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -1031,7 +1031,6 @@ extern char sie_exit; extern int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc); extern int kvm_s390_gisc_unregister(struct kvm *kvm, u32 gisc); -static inline void kvm_arch_hardware_disable(void) {} static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} static inline void kvm_arch_free_memslot(struct kvm *kvm, diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 7ad8252e92c2..bd25076aa19b 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -256,12 +256,6 @@ debug_info_t *kvm_s390_dbf; debug_info_t *kvm_s390_dbf_uv; /* Section: not file related */ -int kvm_arch_hardware_enable(void) -{ - /* every s390 is virtualization enabled ;-) */ - return 0; -} - /* forward declarations */ static void kvm_gmap_notifier(struct gmap *gmap, unsigned long start, unsigned long end); diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index fbeaa9ddef59..8e578311ca9d 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -49,6 +49,7 @@ config KVM select SRCU select INTERVAL_TREE select HAVE_KVM_PM_NOTIFIER if PM + select KVM_GENERIC_HARDWARE_ENABLING help Support hosting fully virtualized guest machines using hardware virtualization extensions. You will need a fairly recent diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 20e207e4c6c1..109b18e2789c 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1441,8 +1441,10 @@ void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_ static inline void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu) {} #endif +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING int kvm_arch_hardware_enable(void); void kvm_arch_hardware_disable(void); +#endif int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu); bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu); int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu); @@ -2074,7 +2076,9 @@ static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu) } } +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING extern bool kvm_rebooting; +#endif extern unsigned int halt_poll_ns; extern unsigned int halt_poll_ns_grow; diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 9fb1ff6f19e5..b74916de5183 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -92,3 +92,6 @@ config KVM_XFER_TO_GUEST_WORK config HAVE_KVM_PM_NOTIFIER bool + +config KVM_GENERIC_HARDWARE_ENABLING + bool diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 6c0bd9a8e27e..3d0678579c5e 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -102,9 +102,6 @@ EXPORT_SYMBOL_GPL(halt_poll_ns_shrink); DEFINE_MUTEX(kvm_lock); LIST_HEAD(vm_list); -static DEFINE_PER_CPU(bool, hardware_enabled); -static int kvm_usage_count; - static struct kmem_cache *kvm_vcpu_cache; static __read_mostly struct preempt_ops kvm_preempt_ops; @@ -146,9 +143,6 @@ static void hardware_disable_all(void); static void kvm_io_bus_destroy(struct kvm_io_bus *bus); -__visible bool kvm_rebooting; -EXPORT_SYMBOL_GPL(kvm_rebooting); - #define KVM_EVENT_CREATE_VM 0 #define KVM_EVENT_DESTROY_VM 1 static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm); @@ -5093,6 +5087,13 @@ static struct miscdevice kvm_dev = { &kvm_chardev_ops, }; +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING +__visible bool kvm_rebooting; +EXPORT_SYMBOL_GPL(kvm_rebooting); + +static DEFINE_PER_CPU(bool, hardware_enabled); +static int kvm_usage_count; + static int __hardware_enable_nolock(void) { if (__this_cpu_read(hardware_enabled)) @@ -5254,6 +5255,17 @@ static struct syscore_ops kvm_syscore_ops = { .suspend = kvm_suspend, .resume = kvm_resume, }; +#else /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */ +static int hardware_enable_all(void) +{ + return 0; +} + +static void hardware_disable_all(void) +{ + +} +#endif /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */ static void kvm_io_bus_destroy(struct kvm_io_bus *bus) { @@ -5942,6 +5954,7 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module) int r; int cpu; +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING r = cpuhp_setup_state_nocalls(CPUHP_AP_KVM_ONLINE, "kvm/cpu:online", kvm_online_cpu, kvm_offline_cpu); if (r) @@ -5949,6 +5962,7 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module) register_reboot_notifier(&kvm_reboot_notifier); register_syscore_ops(&kvm_syscore_ops); +#endif /* A kmem cache lets us meet the alignment requirements of fx_save. */ if (!vcpu_align) @@ -6016,9 +6030,11 @@ out_free_4: free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); kmem_cache_destroy(kvm_vcpu_cache); out_free_3: +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING unregister_syscore_ops(&kvm_syscore_ops); unregister_reboot_notifier(&kvm_reboot_notifier); cpuhp_remove_state_nocalls(CPUHP_AP_KVM_ONLINE); +#endif return r; } EXPORT_SYMBOL_GPL(kvm_init); @@ -6040,9 +6056,11 @@ void kvm_exit(void) kmem_cache_destroy(kvm_vcpu_cache); kvm_vfio_ops_exit(); kvm_async_pf_deinit(); +#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING unregister_syscore_ops(&kvm_syscore_ops); unregister_reboot_notifier(&kvm_reboot_notifier); cpuhp_remove_state_nocalls(CPUHP_AP_KVM_ONLINE); +#endif kvm_irqfd_exit(); } EXPORT_SYMBOL_GPL(kvm_exit); -- cgit v1.2.1