From 2711b8e2b71fa3cce9c28b0f07b75882f141adfe Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 12 May 2023 23:07:29 +0200 Subject: x86/smpboot: Switch to hotplug core state synchronization The new AP state tracking and synchronization mechanism in the CPU hotplug core code allows to remove quite some x86 specific code: 1) The AP alive synchronization based on cpumasks 2) The decision whether an AP can be brought up again Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Tested-by: Michael Kelley Tested-by: Oleksandr Natalenko Tested-by: Helge Deller # parisc Tested-by: Guilherme G. Piccoli # Steam Deck Link: https://lore.kernel.org/r/20230512205256.529657366@linutronix.de --- arch/x86/xen/smp_pv.c | 39 ++++++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 17 deletions(-) (limited to 'arch/x86/xen/smp_pv.c') diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c index be40927667cf..b089fb1cefc6 100644 --- a/arch/x86/xen/smp_pv.c +++ b/arch/x86/xen/smp_pv.c @@ -62,6 +62,7 @@ static void cpu_bringup(void) int cpu; cr4_init(); + cpuhp_ap_sync_alive(); cpu_init(); touch_softlockup_watchdog(); @@ -83,7 +84,7 @@ static void cpu_bringup(void) set_cpu_online(cpu, true); - cpu_set_state_online(cpu); /* Implies full memory barrier. */ + smp_mb(); /* We can take interrupts now: we're officially "up". */ local_irq_enable(); @@ -323,14 +324,6 @@ static int xen_pv_cpu_up(unsigned int cpu, struct task_struct *idle) xen_setup_runstate_info(cpu); - /* - * PV VCPUs are always successfully taken down (see 'while' loop - * in xen_cpu_die()), so -EBUSY is an error. - */ - rc = cpu_check_up_prepare(cpu); - if (rc) - return rc; - /* make sure interrupts start blocked */ per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1; @@ -349,6 +342,11 @@ static int xen_pv_cpu_up(unsigned int cpu, struct task_struct *idle) return 0; } +static void xen_pv_poll_sync_state(void) +{ + HYPERVISOR_sched_op(SCHEDOP_yield, NULL); +} + #ifdef CONFIG_HOTPLUG_CPU static int xen_pv_cpu_disable(void) { @@ -364,18 +362,18 @@ static int xen_pv_cpu_disable(void) static void xen_pv_cpu_die(unsigned int cpu) { - while (HYPERVISOR_vcpu_op(VCPUOP_is_up, - xen_vcpu_nr(cpu), NULL)) { + while (HYPERVISOR_vcpu_op(VCPUOP_is_up, xen_vcpu_nr(cpu), NULL)) { __set_current_state(TASK_UNINTERRUPTIBLE); schedule_timeout(HZ/10); } +} - if (common_cpu_die(cpu) == 0) { - xen_smp_intr_free(cpu); - xen_uninit_lock_cpu(cpu); - xen_teardown_timer(cpu); - xen_pmu_finish(cpu); - } +static void xen_pv_cleanup_dead_cpu(unsigned int cpu) +{ + xen_smp_intr_free(cpu); + xen_uninit_lock_cpu(cpu); + xen_teardown_timer(cpu); + xen_pmu_finish(cpu); } static void __noreturn xen_pv_play_dead(void) /* used only with HOTPLUG_CPU */ @@ -397,6 +395,11 @@ static void xen_pv_cpu_die(unsigned int cpu) BUG(); } +static void xen_pv_cleanup_dead_cpu(unsigned int cpu) +{ + BUG(); +} + static void __noreturn xen_pv_play_dead(void) { BUG(); @@ -437,6 +440,8 @@ static const struct smp_ops xen_smp_ops __initconst = { .cpu_up = xen_pv_cpu_up, .cpu_die = xen_pv_cpu_die, + .cleanup_dead_cpu = xen_pv_cleanup_dead_cpu, + .poll_sync_state = xen_pv_poll_sync_state, .cpu_disable = xen_pv_cpu_disable, .play_dead = xen_pv_play_dead, -- cgit