14ccefbe5SStefano Stabellini /* 24ccefbe5SStefano Stabellini * Xen stolen ticks accounting. 34ccefbe5SStefano Stabellini */ 44ccefbe5SStefano Stabellini #include <linux/kernel.h> 54ccefbe5SStefano Stabellini #include <linux/kernel_stat.h> 64ccefbe5SStefano Stabellini #include <linux/math64.h> 74ccefbe5SStefano Stabellini #include <linux/gfp.h> 84ccefbe5SStefano Stabellini 9ecb23dc6SJuergen Gross #include <asm/paravirt.h> 104ccefbe5SStefano Stabellini #include <asm/xen/hypervisor.h> 114ccefbe5SStefano Stabellini #include <asm/xen/hypercall.h> 124ccefbe5SStefano Stabellini 134ccefbe5SStefano Stabellini #include <xen/events.h> 144ccefbe5SStefano Stabellini #include <xen/features.h> 154ccefbe5SStefano Stabellini #include <xen/interface/xen.h> 164ccefbe5SStefano Stabellini #include <xen/interface/vcpu.h> 174ccefbe5SStefano Stabellini #include <xen/xen-ops.h> 184ccefbe5SStefano Stabellini 194ccefbe5SStefano Stabellini /* runstate info updated by Xen */ 204ccefbe5SStefano Stabellini static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate); 214ccefbe5SStefano Stabellini 224ccefbe5SStefano Stabellini /* return an consistent snapshot of 64-bit time/counter value */ 234ccefbe5SStefano Stabellini static u64 get64(const u64 *p) 244ccefbe5SStefano Stabellini { 254ccefbe5SStefano Stabellini u64 ret; 264ccefbe5SStefano Stabellini 274ccefbe5SStefano Stabellini if (BITS_PER_LONG < 64) { 284ccefbe5SStefano Stabellini u32 *p32 = (u32 *)p; 292dd887e3SStefano Stabellini u32 h, l, h2; 304ccefbe5SStefano Stabellini 314ccefbe5SStefano Stabellini /* 324ccefbe5SStefano Stabellini * Read high then low, and then make sure high is 334ccefbe5SStefano Stabellini * still the same; this will only loop if low wraps 344ccefbe5SStefano Stabellini * and carries into high. 354ccefbe5SStefano Stabellini * XXX some clean way to make this endian-proof? 364ccefbe5SStefano Stabellini */ 374ccefbe5SStefano Stabellini do { 382dd887e3SStefano Stabellini h = READ_ONCE(p32[1]); 392dd887e3SStefano Stabellini l = READ_ONCE(p32[0]); 402dd887e3SStefano Stabellini h2 = READ_ONCE(p32[1]); 412dd887e3SStefano Stabellini } while(h2 != h); 424ccefbe5SStefano Stabellini 434ccefbe5SStefano Stabellini ret = (((u64)h) << 32) | l; 444ccefbe5SStefano Stabellini } else 452dd887e3SStefano Stabellini ret = READ_ONCE(*p); 464ccefbe5SStefano Stabellini 474ccefbe5SStefano Stabellini return ret; 484ccefbe5SStefano Stabellini } 494ccefbe5SStefano Stabellini 506ba286adSJuergen Gross static void xen_get_runstate_snapshot_cpu(struct vcpu_runstate_info *res, 516ba286adSJuergen Gross unsigned int cpu) 524ccefbe5SStefano Stabellini { 534ccefbe5SStefano Stabellini u64 state_time; 544ccefbe5SStefano Stabellini struct vcpu_runstate_info *state; 554ccefbe5SStefano Stabellini 564ccefbe5SStefano Stabellini BUG_ON(preemptible()); 574ccefbe5SStefano Stabellini 586ba286adSJuergen Gross state = per_cpu_ptr(&xen_runstate, cpu); 594ccefbe5SStefano Stabellini 604ccefbe5SStefano Stabellini do { 614ccefbe5SStefano Stabellini state_time = get64(&state->state_entry_time); 626ba286adSJuergen Gross rmb(); /* Hypervisor might update data. */ 632dd887e3SStefano Stabellini *res = READ_ONCE(*state); 646ba286adSJuergen Gross rmb(); /* Hypervisor might update data. */ 656ba286adSJuergen Gross } while (get64(&state->state_entry_time) != state_time || 666ba286adSJuergen Gross (state_time & XEN_RUNSTATE_UPDATE)); 676ba286adSJuergen Gross } 686ba286adSJuergen Gross 696ba286adSJuergen Gross /* 706ba286adSJuergen Gross * Runstate accounting 716ba286adSJuergen Gross */ 726ba286adSJuergen Gross void xen_get_runstate_snapshot(struct vcpu_runstate_info *res) 736ba286adSJuergen Gross { 746ba286adSJuergen Gross xen_get_runstate_snapshot_cpu(res, smp_processor_id()); 754ccefbe5SStefano Stabellini } 764ccefbe5SStefano Stabellini 774ccefbe5SStefano Stabellini /* return true when a vcpu could run but has no real cpu to run on */ 784ccefbe5SStefano Stabellini bool xen_vcpu_stolen(int vcpu) 794ccefbe5SStefano Stabellini { 804ccefbe5SStefano Stabellini return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable; 814ccefbe5SStefano Stabellini } 824ccefbe5SStefano Stabellini 83ecb23dc6SJuergen Gross static u64 xen_steal_clock(int cpu) 84ecb23dc6SJuergen Gross { 85ecb23dc6SJuergen Gross struct vcpu_runstate_info state; 86ecb23dc6SJuergen Gross 876ba286adSJuergen Gross xen_get_runstate_snapshot_cpu(&state, cpu); 88ecb23dc6SJuergen Gross return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline]; 89ecb23dc6SJuergen Gross } 90ecb23dc6SJuergen Gross 914ccefbe5SStefano Stabellini void xen_setup_runstate_info(int cpu) 924ccefbe5SStefano Stabellini { 934ccefbe5SStefano Stabellini struct vcpu_register_runstate_memory_area area; 944ccefbe5SStefano Stabellini 954ccefbe5SStefano Stabellini area.addr.v = &per_cpu(xen_runstate, cpu); 964ccefbe5SStefano Stabellini 974ccefbe5SStefano Stabellini if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area, 98ad5475f9SVitaly Kuznetsov xen_vcpu_nr(cpu), &area)) 994ccefbe5SStefano Stabellini BUG(); 1004ccefbe5SStefano Stabellini } 1014ccefbe5SStefano Stabellini 102ecb23dc6SJuergen Gross void __init xen_time_setup_guest(void) 103ecb23dc6SJuergen Gross { 1046ba286adSJuergen Gross bool xen_runstate_remote; 1056ba286adSJuergen Gross 1066ba286adSJuergen Gross xen_runstate_remote = !HYPERVISOR_vm_assist(VMASST_CMD_enable, 1076ba286adSJuergen Gross VMASST_TYPE_runstate_update_flag); 1086ba286adSJuergen Gross 109ecb23dc6SJuergen Gross pv_time_ops.steal_clock = xen_steal_clock; 110ecb23dc6SJuergen Gross 111ecb23dc6SJuergen Gross static_key_slow_inc(¶virt_steal_enabled); 1126ba286adSJuergen Gross if (xen_runstate_remote) 1136ba286adSJuergen Gross static_key_slow_inc(¶virt_steal_rq_enabled); 114ecb23dc6SJuergen Gross } 115