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KVM: Opt out of generic hardware enabling on s390 and PPC

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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@google.com>
Acked-by: Anup Patel <anup@brainfault.org>
Message-Id: <20221130230934.1014142-50-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2022-11-30 23:09:33 +00:00 committed by Paolo Bonzini
parent 35774a9f94
commit 441f7bfa99
11 changed files with 35 additions and 19 deletions
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1
arch/arm64/kvm/Kconfig
View File

@ -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

1
arch/mips/kvm/Kconfig
View File

@ -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.

1
arch/powerpc/include/asm/kvm_host.h
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@ -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) {}

5
arch/powerpc/kvm/powerpc.c
View File

@ -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;

1
arch/riscv/kvm/Kconfig
View File

@ -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

1
arch/s390/include/asm/kvm_host.h
View File

@ -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,

6
arch/s390/kvm/kvm-s390.c
View File

@ -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);

1
arch/x86/kvm/Kconfig
View File

@ -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

4
include/linux/kvm_host.h
View File

@ -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;

3
virt/kvm/Kconfig
View File

@ -92,3 +92,6 @@ config KVM_XFER_TO_GUEST_WORK
config HAVE_KVM_PM_NOTIFIER
bool
config KVM_GENERIC_HARDWARE_ENABLING
bool

30
virt/kvm/kvm_main.c
View File

@ -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);