Re: [v4 2/4] arm64: kvm: add kvm cpu hotplug

On 05/26/2015 06:35 PM, Marc Zyngier wrote:

On 08/05/15 02:18, AKASHI Takahiro wrote:

...

This patch allows cpu cores to be up and down by adding kvm_arch_hardware_enable/isable(). This way, especially in kexec case, cores are reset to initial states and kexec can gracefully shutdown the system and reboot a new kernel from EL2.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org

arch/arm/include/asm/kvm_host.h | 1 - arch/arm/kvm/arm.c | 29 +++++++++++++++++++---------- arch/arm64/include/asm/kvm_host.h | 1 - 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index 41008cd..ca97764 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -237,7 +237,6 @@ void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);

struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);

-static inline void kvm_arch_hardware_disable(void) {} static inline void kvm_arch_hardware_unsetup(void) {} static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 251ab9e..e989925 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -87,11 +87,6 @@ struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void) return &kvm_arm_running_vcpu; }

-int kvm_arch_hardware_enable(void) -{

• return 0;

-}

• int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) { return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;

@@ -885,6 +880,9 @@ static void cpu_init_hyp_mode(void *dummy)

Since you removed the IPI, why do you keep the dummy argument?

Yeah, will remove it.

...

unsigned long stack_page; unsigned long vector_ptr;

• if (__hyp_get_vectors() != hyp_default_vectors)

• return;
  

• /* Switch from the HYP stub to our own HYP init vector */ __hyp_set_vectors(kvm_get_idmap_vector());

@@ -921,6 +919,10 @@ static int hyp_init_cpu_notify(struct notifier_block *self, if (__hyp_get_vectors() == hyp_default_vectors) cpu_init_hyp_mode(NULL); break;

• case CPU_DYING:

• case CPU_DYING_FROZEN:

• kvm_cpu_reset(NULL);
  

• break;
  

  }

  return NOTIFY_OK;

@@ -936,6 +938,7 @@ static int hyp_init_cpu_pm_notifier(struct notifier_block *self, void *v) { if (cmd == CPU_PM_EXIT &&

•    kvm_arm_get_running_vcpu() &&
   __hyp_get_vectors() == hyp_default_vectors) {
  

  cpu_init_hyp_mode(NULL); return NOTIFY_OK;

@@ -1039,11 +1042,6 @@ static int init_hyp_mode(void) }

/*

• * Execute the init code on each CPU.
  

• */
  

• on_each_cpu(cpu_init_hyp_mode, NULL, 1);
• /*
  • Init HYP view of VGIC
  */ err = kvm_vgic_hyp_init();

@@ -1144,6 +1142,17 @@ out_err: return err; }

+int kvm_arch_hardware_enable(void) +{

• cpu_init_hyp_mode(NULL);
• return 0;

+}

+void kvm_arch_hardware_disable(void) +{

• kvm_cpu_reset(NULL);

+}

Bahhh... Just rename cpu_init_hyp_mode to kvm_arch_hardware_enable, and kvM_cpu_reset to kvm_arch_hardware_disable. I don't see the point of keeping this indirection.

Historical reason ... Anyway, if we don't have to add anything else here, yes, I will rename them.

-Takahiro AKASHI

...

/* NOP: Compiling as a module not supported */ void kvm_arch_exit(void) { diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 6a8da9c..831e6a4 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -262,7 +262,6 @@ static inline void vgic_arch_setup(const struct vgic_params *vgic) } }

-static inline void kvm_arch_hardware_disable(void) {} static inline void kvm_arch_hardware_unsetup(void) {} static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}