1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 24ccefbe5SStefano Stabellini /* 34ccefbe5SStefano Stabellini * Xen stolen ticks accounting. 44ccefbe5SStefano Stabellini */ 54ccefbe5SStefano Stabellini #include <linux/kernel.h> 64ccefbe5SStefano Stabellini #include <linux/kernel_stat.h> 74ccefbe5SStefano Stabellini #include <linux/math64.h> 84ccefbe5SStefano Stabellini #include <linux/gfp.h> 94ccefbe5SStefano Stabellini 10ecb23dc6SJuergen Gross #include <asm/paravirt.h> 114ccefbe5SStefano Stabellini #include <asm/xen/hypervisor.h> 124ccefbe5SStefano Stabellini #include <asm/xen/hypercall.h> 134ccefbe5SStefano Stabellini 144ccefbe5SStefano Stabellini #include <xen/events.h> 154ccefbe5SStefano Stabellini #include <xen/features.h> 164ccefbe5SStefano Stabellini #include <xen/interface/xen.h> 174ccefbe5SStefano Stabellini #include <xen/interface/vcpu.h> 184ccefbe5SStefano Stabellini #include <xen/xen-ops.h> 194ccefbe5SStefano Stabellini 204ccefbe5SStefano Stabellini /* runstate info updated by Xen */ 214ccefbe5SStefano Stabellini static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate); 224ccefbe5SStefano Stabellini 234ccefbe5SStefano Stabellini /* return an consistent snapshot of 64-bit time/counter value */ 244ccefbe5SStefano Stabellini static u64 get64(const u64 *p) 254ccefbe5SStefano Stabellini { 264ccefbe5SStefano Stabellini u64 ret; 274ccefbe5SStefano Stabellini 284ccefbe5SStefano Stabellini if (BITS_PER_LONG < 64) { 294ccefbe5SStefano Stabellini u32 *p32 = (u32 *)p; 302dd887e3SStefano Stabellini u32 h, l, h2; 314ccefbe5SStefano Stabellini 324ccefbe5SStefano Stabellini /* 334ccefbe5SStefano Stabellini * Read high then low, and then make sure high is 344ccefbe5SStefano Stabellini * still the same; this will only loop if low wraps 354ccefbe5SStefano Stabellini * and carries into high. 364ccefbe5SStefano Stabellini * XXX some clean way to make this endian-proof? 374ccefbe5SStefano Stabellini */ 384ccefbe5SStefano Stabellini do { 392dd887e3SStefano Stabellini h = READ_ONCE(p32[1]); 402dd887e3SStefano Stabellini l = READ_ONCE(p32[0]); 412dd887e3SStefano Stabellini h2 = READ_ONCE(p32[1]); 422dd887e3SStefano Stabellini } while(h2 != h); 434ccefbe5SStefano Stabellini 444ccefbe5SStefano Stabellini ret = (((u64)h) << 32) | l; 454ccefbe5SStefano Stabellini } else 462dd887e3SStefano Stabellini ret = READ_ONCE(*p); 474ccefbe5SStefano Stabellini 484ccefbe5SStefano Stabellini return ret; 494ccefbe5SStefano Stabellini } 504ccefbe5SStefano Stabellini 516ba286adSJuergen Gross static void xen_get_runstate_snapshot_cpu(struct vcpu_runstate_info *res, 526ba286adSJuergen Gross unsigned int cpu) 534ccefbe5SStefano Stabellini { 544ccefbe5SStefano Stabellini u64 state_time; 554ccefbe5SStefano Stabellini struct vcpu_runstate_info *state; 564ccefbe5SStefano Stabellini 574ccefbe5SStefano Stabellini BUG_ON(preemptible()); 584ccefbe5SStefano Stabellini 596ba286adSJuergen Gross state = per_cpu_ptr(&xen_runstate, cpu); 604ccefbe5SStefano Stabellini 614ccefbe5SStefano Stabellini do { 624ccefbe5SStefano Stabellini state_time = get64(&state->state_entry_time); 636ba286adSJuergen Gross rmb(); /* Hypervisor might update data. */ 642dd887e3SStefano Stabellini *res = READ_ONCE(*state); 656ba286adSJuergen Gross rmb(); /* Hypervisor might update data. */ 666ba286adSJuergen Gross } while (get64(&state->state_entry_time) != state_time || 676ba286adSJuergen Gross (state_time & XEN_RUNSTATE_UPDATE)); 686ba286adSJuergen Gross } 696ba286adSJuergen Gross 706ba286adSJuergen Gross /* 716ba286adSJuergen Gross * Runstate accounting 726ba286adSJuergen Gross */ 736ba286adSJuergen Gross void xen_get_runstate_snapshot(struct vcpu_runstate_info *res) 746ba286adSJuergen Gross { 756ba286adSJuergen Gross xen_get_runstate_snapshot_cpu(res, smp_processor_id()); 764ccefbe5SStefano Stabellini } 774ccefbe5SStefano Stabellini 784ccefbe5SStefano Stabellini /* return true when a vcpu could run but has no real cpu to run on */ 794ccefbe5SStefano Stabellini bool xen_vcpu_stolen(int vcpu) 804ccefbe5SStefano Stabellini { 814ccefbe5SStefano Stabellini return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable; 824ccefbe5SStefano Stabellini } 834ccefbe5SStefano Stabellini 84d34c30ccSJuergen Gross u64 xen_steal_clock(int cpu) 85ecb23dc6SJuergen Gross { 86ecb23dc6SJuergen Gross struct vcpu_runstate_info state; 87ecb23dc6SJuergen Gross 886ba286adSJuergen Gross xen_get_runstate_snapshot_cpu(&state, cpu); 89ecb23dc6SJuergen Gross return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline]; 90ecb23dc6SJuergen Gross } 91ecb23dc6SJuergen Gross 924ccefbe5SStefano Stabellini void xen_setup_runstate_info(int cpu) 934ccefbe5SStefano Stabellini { 944ccefbe5SStefano Stabellini struct vcpu_register_runstate_memory_area area; 954ccefbe5SStefano Stabellini 964ccefbe5SStefano Stabellini area.addr.v = &per_cpu(xen_runstate, cpu); 974ccefbe5SStefano Stabellini 984ccefbe5SStefano Stabellini if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area, 99ad5475f9SVitaly Kuznetsov xen_vcpu_nr(cpu), &area)) 1004ccefbe5SStefano Stabellini BUG(); 1014ccefbe5SStefano Stabellini } 1024ccefbe5SStefano Stabellini 103ecb23dc6SJuergen Gross void __init xen_time_setup_guest(void) 104ecb23dc6SJuergen Gross { 1056ba286adSJuergen Gross bool xen_runstate_remote; 1066ba286adSJuergen Gross 1076ba286adSJuergen Gross xen_runstate_remote = !HYPERVISOR_vm_assist(VMASST_CMD_enable, 1086ba286adSJuergen Gross VMASST_TYPE_runstate_update_flag); 1096ba286adSJuergen Gross 110ecb23dc6SJuergen Gross pv_time_ops.steal_clock = xen_steal_clock; 111ecb23dc6SJuergen Gross 112ecb23dc6SJuergen Gross static_key_slow_inc(¶virt_steal_enabled); 1136ba286adSJuergen Gross if (xen_runstate_remote) 1146ba286adSJuergen Gross static_key_slow_inc(¶virt_steal_rq_enabled); 115ecb23dc6SJuergen Gross } 116