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 504ccefbe5SStefano Stabellini /* 514ccefbe5SStefano Stabellini * Runstate accounting 524ccefbe5SStefano Stabellini */ 534ccefbe5SStefano Stabellini void xen_get_runstate_snapshot(struct vcpu_runstate_info *res) 544ccefbe5SStefano Stabellini { 554ccefbe5SStefano Stabellini u64 state_time; 564ccefbe5SStefano Stabellini struct vcpu_runstate_info *state; 574ccefbe5SStefano Stabellini 584ccefbe5SStefano Stabellini BUG_ON(preemptible()); 594ccefbe5SStefano Stabellini 604ccefbe5SStefano Stabellini state = this_cpu_ptr(&xen_runstate); 614ccefbe5SStefano Stabellini 624ccefbe5SStefano Stabellini /* 634ccefbe5SStefano Stabellini * The runstate info is always updated by the hypervisor on 644ccefbe5SStefano Stabellini * the current CPU, so there's no need to use anything 654ccefbe5SStefano Stabellini * stronger than a compiler barrier when fetching it. 664ccefbe5SStefano Stabellini */ 674ccefbe5SStefano Stabellini do { 684ccefbe5SStefano Stabellini state_time = get64(&state->state_entry_time); 692dd887e3SStefano Stabellini *res = READ_ONCE(*state); 704ccefbe5SStefano Stabellini } while (get64(&state->state_entry_time) != state_time); 714ccefbe5SStefano Stabellini } 724ccefbe5SStefano Stabellini 734ccefbe5SStefano Stabellini /* return true when a vcpu could run but has no real cpu to run on */ 744ccefbe5SStefano Stabellini bool xen_vcpu_stolen(int vcpu) 754ccefbe5SStefano Stabellini { 764ccefbe5SStefano Stabellini return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable; 774ccefbe5SStefano Stabellini } 784ccefbe5SStefano Stabellini 79ecb23dc6SJuergen Gross static u64 xen_steal_clock(int cpu) 80ecb23dc6SJuergen Gross { 81ecb23dc6SJuergen Gross struct vcpu_runstate_info state; 82ecb23dc6SJuergen Gross 83ecb23dc6SJuergen Gross BUG_ON(cpu != smp_processor_id()); 84ecb23dc6SJuergen Gross xen_get_runstate_snapshot(&state); 85ecb23dc6SJuergen Gross return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline]; 86ecb23dc6SJuergen Gross } 87ecb23dc6SJuergen Gross 884ccefbe5SStefano Stabellini void xen_setup_runstate_info(int cpu) 894ccefbe5SStefano Stabellini { 904ccefbe5SStefano Stabellini struct vcpu_register_runstate_memory_area area; 914ccefbe5SStefano Stabellini 924ccefbe5SStefano Stabellini area.addr.v = &per_cpu(xen_runstate, cpu); 934ccefbe5SStefano Stabellini 944ccefbe5SStefano Stabellini if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area, 954ccefbe5SStefano Stabellini cpu, &area)) 964ccefbe5SStefano Stabellini BUG(); 974ccefbe5SStefano Stabellini } 984ccefbe5SStefano Stabellini 99ecb23dc6SJuergen Gross void __init xen_time_setup_guest(void) 100ecb23dc6SJuergen Gross { 101ecb23dc6SJuergen Gross pv_time_ops.steal_clock = xen_steal_clock; 102ecb23dc6SJuergen Gross 103ecb23dc6SJuergen Gross static_key_slow_inc(¶virt_steal_enabled); 104ecb23dc6SJuergen Gross /* 105ecb23dc6SJuergen Gross * We can't set paravirt_steal_rq_enabled as this would require the 106ecb23dc6SJuergen Gross * capability to read another cpu's runstate info. 107ecb23dc6SJuergen Gross */ 108ecb23dc6SJuergen Gross } 109