| Message ID | 20240608000639.3295768-6-seanjc@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: Register cpuhp/syscore callbacks when enabling virt | expand |
On 6/8/24 02:06, Sean Christopherson wrote: > Add arch hooks that are invoked when KVM enables/disable virtualization. > x86 will use the hooks to register an "emergency disable" callback, which > is essentially an x86-specific shutdown notifier that is used when the > kernel is doing an emergency reboot/shutdown/kexec. > > Add comments for the declarations to help arch code understand exactly > when the callbacks are invoked. Alternatively, the APIs themselves could > communicate most of the same info, but kvm_arch_pre_enable_virtualization() > and kvm_arch_post_disable_virtualization() are a bit cumbersome, and make > it a bit less obvious that they are intended to be implemented as a pair. > > Reviewed-by: Chao Gao <chao.gao@intel.com> > Reviewed-by: Kai Huang <kai.huang@intel.com> > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > include/linux/kvm_host.h | 14 ++++++++++++++ > virt/kvm/kvm_main.c | 14 ++++++++++++++ > 2 files changed, 28 insertions(+) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 96ad3e8b9ddb..12ef3beb4e47 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -1514,6 +1514,20 @@ static inline void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu) {} > #endif > > #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING > +/* > + * kvm_arch_{enable,disable}_virtualization() are called on one CPU, under > + * kvm_usage_lock, immediately after/before 0=>1 and 1=>0 transitions of > + * kvm_usage_count, i.e. at the beginning of the generic hardware enabling > + * sequence, and at the end of the generic hardware disabling sequence. > + */ > +void kvm_arch_enable_virtualization(void); > +void kvm_arch_disable_virtualization(void); > +/* > + * kvm_arch_hardware_{enable,disable}() are called on "every" CPU to do the > + * actual twiddling of hardware bits. The hooks are called all online CPUs > + * when KVM enables/disabled virtualization. Enabling/disabling is also done > + * when a CPU is onlined/offlined (or Resumed/Suspended). > + */ > int kvm_arch_hardware_enable(void); > void kvm_arch_hardware_disable(void); Since you are at it, rename these to kvm_arch_{enable,disable}_virtualization_cpu()? Paolo > #endif > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 7bdd744e4821..e20189a89a64 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -5505,6 +5505,16 @@ static DEFINE_PER_CPU(bool, hardware_enabled); > static DEFINE_MUTEX(kvm_usage_lock); > static int kvm_usage_count; > > +__weak void kvm_arch_enable_virtualization(void) > +{ > + > +} > + > +__weak void kvm_arch_disable_virtualization(void) > +{ > + > +} > + > static int __kvm_enable_virtualization(void) > { > if (__this_cpu_read(hardware_enabled)) > @@ -5604,6 +5614,8 @@ static int kvm_enable_virtualization(void) > if (kvm_usage_count++) > return 0; > > + kvm_arch_enable_virtualization(); > + > r = cpuhp_setup_state(CPUHP_AP_KVM_ONLINE, "kvm/cpu:online", > kvm_online_cpu, kvm_offline_cpu); > if (r) > @@ -5634,6 +5646,7 @@ static int kvm_enable_virtualization(void) > unregister_syscore_ops(&kvm_syscore_ops); > cpuhp_remove_state(CPUHP_AP_KVM_ONLINE); > err_cpuhp: > + kvm_arch_disable_virtualization(); > --kvm_usage_count; > return r; > } > @@ -5647,6 +5660,7 @@ static void kvm_disable_virtualization(void) > > unregister_syscore_ops(&kvm_syscore_ops); > cpuhp_remove_state(CPUHP_AP_KVM_ONLINE); > + kvm_arch_disable_virtualization(); > } > > static int kvm_init_virtualization(void)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 96ad3e8b9ddb..12ef3beb4e47 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1514,6 +1514,20 @@ static inline void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu) {} #endif #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING +/* + * kvm_arch_{enable,disable}_virtualization() are called on one CPU, under + * kvm_usage_lock, immediately after/before 0=>1 and 1=>0 transitions of + * kvm_usage_count, i.e. at the beginning of the generic hardware enabling + * sequence, and at the end of the generic hardware disabling sequence. + */ +void kvm_arch_enable_virtualization(void); +void kvm_arch_disable_virtualization(void); +/* + * kvm_arch_hardware_{enable,disable}() are called on "every" CPU to do the + * actual twiddling of hardware bits. The hooks are called all online CPUs + * when KVM enables/disabled virtualization. Enabling/disabling is also done + * when a CPU is onlined/offlined (or Resumed/Suspended). + */ int kvm_arch_hardware_enable(void); void kvm_arch_hardware_disable(void); #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 7bdd744e4821..e20189a89a64 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -5505,6 +5505,16 @@ static DEFINE_PER_CPU(bool, hardware_enabled); static DEFINE_MUTEX(kvm_usage_lock); static int kvm_usage_count; +__weak void kvm_arch_enable_virtualization(void) +{ + +} + +__weak void kvm_arch_disable_virtualization(void) +{ + +} + static int __kvm_enable_virtualization(void) { if (__this_cpu_read(hardware_enabled)) @@ -5604,6 +5614,8 @@ static int kvm_enable_virtualization(void) if (kvm_usage_count++) return 0; + kvm_arch_enable_virtualization(); + r = cpuhp_setup_state(CPUHP_AP_KVM_ONLINE, "kvm/cpu:online", kvm_online_cpu, kvm_offline_cpu); if (r) @@ -5634,6 +5646,7 @@ static int kvm_enable_virtualization(void) unregister_syscore_ops(&kvm_syscore_ops); cpuhp_remove_state(CPUHP_AP_KVM_ONLINE); err_cpuhp: + kvm_arch_disable_virtualization(); --kvm_usage_count; return r; } @@ -5647,6 +5660,7 @@ static void kvm_disable_virtualization(void) unregister_syscore_ops(&kvm_syscore_ops); cpuhp_remove_state(CPUHP_AP_KVM_ONLINE); + kvm_arch_disable_virtualization(); } static int kvm_init_virtualization(void)