arm64: kvm: allows kvm cpu hotplug

[firefly-linux-kernel-4.4.55.git] / arch / arm / kvm / arm.c

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 99b270300ab1f059810a367d4df30367a7959fa3..4cddf20cdb824394d5368bb5cd10a4eadff2d06c 100644 (file)
--- 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 <linux/cpu.h>
 #include <linux/cpu_pm.h>
 #include <linux/errno.h>
 #include <linux/err.h>
@@ -65,6 +64,8 @@ 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());
@@ -89,11 +90,6 @@ 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;
@@ -964,11 +960,6 @@ 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;
@@ -996,43 +987,87 @@ 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 = {
@@ -1067,18 +1102,12 @@ 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
@@ -1096,9 +1125,10 @@ static int init_subsystems(void)
        case -ENODEV:
        case -ENXIO:
                vgic_present = false;
+               err = 0;
                break;
        default:
-               return err;
+               goto out;
        }
 
        /*
@@ -1106,12 +1136,15 @@ 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)
@@ -1128,11 +1161,6 @@ 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);
@@ -1219,11 +1247,6 @@ 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