From 67f6919766620e7ea7aab11a6a3470dc7b451359 Mon Sep 17 00:00:00 2001 From: AKASHI Takahiro Date: Wed, 27 Apr 2016 17:47:05 +0100 Subject: arm64: kvm: allows kvm cpu hotplug The current kvm implementation on arm64 does cpu-specific initialization at system boot, and has no way to gracefully shutdown a core in terms of kvm. This prevents kexec from rebooting the system at EL2. This patch adds a cpu tear-down function and also puts an existing cpu-init code into a separate function, kvm_arch_hardware_disable() and kvm_arch_hardware_enable() respectively. We don't need the arm64 specific cpu hotplug hook any more. Since this patch modifies common code between arm and arm64, one stub definition, __cpu_reset_hyp_mode(), is added on arm side to avoid compilation errors. Signed-off-by: AKASHI Takahiro [Rebase, added separate VHE init/exit path, changed resets use of kvm_call_hyp() to the __version, en/disabled hardware in init_subsystems(), added icache maintenance to __kvm_hyp_reset() and removed lr restore, removed guest-enter after teardown handling] Signed-off-by: James Morse Acked-by: Marc Zyngier Signed-off-by: Will Deacon --- arch/arm/kvm/arm.c | 119 ++++++++++++++++++++++++++++++++--------------------- 1 file changed, 71 insertions(+), 48 deletions(-) (limited to 'arch/arm/kvm/arm.c') diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index b5384311dec4..1687e1450c3a 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -16,7 +16,6 @@ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ -#include #include #include #include @@ -66,6 +65,8 @@ static DEFINE_SPINLOCK(kvm_vmid_lock); static bool vgic_present; +static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled); + static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu) { BUG_ON(preemptible()); @@ -90,11 +91,6 @@ 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; @@ -1033,11 +1029,6 @@ long kvm_arch_vm_ioctl(struct file *filp, } } -static void cpu_init_stage2(void *dummy) -{ - __cpu_init_stage2(); -} - static void cpu_init_hyp_mode(void *dummy) { phys_addr_t boot_pgd_ptr; @@ -1065,43 +1056,87 @@ static void cpu_hyp_reinit(void) { if (is_kernel_in_hyp_mode()) { /* - * cpu_init_stage2() is safe to call even if the PM + * __cpu_init_stage2() is safe to call even if the PM * event was cancelled before the CPU was reset. */ - cpu_init_stage2(NULL); + __cpu_init_stage2(); } else { if (__hyp_get_vectors() == hyp_default_vectors) cpu_init_hyp_mode(NULL); } } -static int hyp_init_cpu_notify(struct notifier_block *self, - unsigned long action, void *cpu) +static void cpu_hyp_reset(void) +{ + phys_addr_t boot_pgd_ptr; + phys_addr_t phys_idmap_start; + + if (!is_kernel_in_hyp_mode()) { + boot_pgd_ptr = kvm_mmu_get_boot_httbr(); + phys_idmap_start = kvm_get_idmap_start(); + + __cpu_reset_hyp_mode(boot_pgd_ptr, phys_idmap_start); + } +} + +static void _kvm_arch_hardware_enable(void *discard) { - switch (action) { - case CPU_STARTING: - case CPU_STARTING_FROZEN: + if (!__this_cpu_read(kvm_arm_hardware_enabled)) { cpu_hyp_reinit(); + __this_cpu_write(kvm_arm_hardware_enabled, 1); } +} + +int kvm_arch_hardware_enable(void) +{ + _kvm_arch_hardware_enable(NULL); + return 0; +} - return NOTIFY_OK; +static void _kvm_arch_hardware_disable(void *discard) +{ + if (__this_cpu_read(kvm_arm_hardware_enabled)) { + cpu_hyp_reset(); + __this_cpu_write(kvm_arm_hardware_enabled, 0); + } } -static struct notifier_block hyp_init_cpu_nb = { - .notifier_call = hyp_init_cpu_notify, -}; +void kvm_arch_hardware_disable(void) +{ + _kvm_arch_hardware_disable(NULL); +} #ifdef CONFIG_CPU_PM static int hyp_init_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd, void *v) { - if (cmd == CPU_PM_EXIT) { - cpu_hyp_reinit(); + /* + * kvm_arm_hardware_enabled is left with its old value over + * PM_ENTER->PM_EXIT. It is used to indicate PM_EXIT should + * re-enable hyp. + */ + switch (cmd) { + case CPU_PM_ENTER: + if (__this_cpu_read(kvm_arm_hardware_enabled)) + /* + * don't update kvm_arm_hardware_enabled here + * so that the hardware will be re-enabled + * when we resume. See below. + */ + cpu_hyp_reset(); + + return NOTIFY_OK; + case CPU_PM_EXIT: + if (__this_cpu_read(kvm_arm_hardware_enabled)) + /* The hardware was enabled before suspend. */ + cpu_hyp_reinit(); + return NOTIFY_OK; - } - return NOTIFY_DONE; + default: + return NOTIFY_DONE; + } } static struct notifier_block hyp_init_cpu_pm_nb = { @@ -1136,18 +1171,12 @@ static int init_common_resources(void) static int init_subsystems(void) { - int err; + int err = 0; /* - * Register CPU Hotplug notifier + * Enable hardware so that subsystem initialisation can access EL2. */ - cpu_notifier_register_begin(); - err = __register_cpu_notifier(&hyp_init_cpu_nb); - cpu_notifier_register_done(); - if (err) { - kvm_err("Cannot register KVM init CPU notifier (%d)\n", err); - return err; - } + on_each_cpu(_kvm_arch_hardware_enable, NULL, 1); /* * Register CPU lower-power notifier @@ -1165,9 +1194,10 @@ static int init_subsystems(void) case -ENODEV: case -ENXIO: vgic_present = false; + err = 0; break; default: - return err; + goto out; } /* @@ -1175,12 +1205,15 @@ static int init_subsystems(void) */ err = kvm_timer_hyp_init(); if (err) - return err; + goto out; kvm_perf_init(); kvm_coproc_table_init(); - return 0; +out: + on_each_cpu(_kvm_arch_hardware_disable, NULL, 1); + + return err; } static void teardown_hyp_mode(void) @@ -1197,11 +1230,6 @@ static void teardown_hyp_mode(void) static int init_vhe_mode(void) { - /* - * Execute the init code on each CPU. - */ - on_each_cpu(cpu_init_stage2, NULL, 1); - /* set size of VMID supported by CPU */ kvm_vmid_bits = kvm_get_vmid_bits(); kvm_info("%d-bit VMID\n", kvm_vmid_bits); @@ -1288,11 +1316,6 @@ static int init_hyp_mode(void) } } - /* - * Execute the init code on each CPU. - */ - on_each_cpu(cpu_init_hyp_mode, NULL, 1); - #ifndef CONFIG_HOTPLUG_CPU free_boot_hyp_pgd(); #endif -- cgit v1.2.3-59-g8ed1b