On Thu, Nov 3, 2022 at 4:50 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
>
> 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 <seanjc@xxxxxxxxxx>
For KVM RISC-V:
Acked-by: Anup Patel <anup@xxxxxxxxxxxxxx>
Thanks,
Anup
> ---
> 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 815cc118c675..0a7d2116b27b 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 51268be60dac..ed426c9ee0e9 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -436,11 +436,6 @@ 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 b1e98a9ed152..d3e4b5d7013a 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -1023,7 +1023,6 @@ 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 949231f1393e..129c159ab5ee 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -248,12 +248,6 @@ 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 0b96d836a051..23c89c1e7788 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 800f9470e36b..d28df77345e1 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -86,3 +86,6 @@ 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 859bc27091cd..6736b36cf469 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);
> @@ -5005,6 +4999,13 @@ 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))
> @@ -5171,6 +5172,17 @@ 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)
> {
> @@ -5859,6 +5871,7 @@ 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)
> @@ -5866,6 +5879,7 @@ 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)
> @@ -5933,9 +5947,11 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
> 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);
> @@ -5957,9 +5973,11 @@ 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);
> --
> 2.38.1.431.g37b22c650d-goog
>
