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 94ccefbe5SStefano Stabellini #include <asm/xen/hypervisor.h> 104ccefbe5SStefano Stabellini #include <asm/xen/hypercall.h> 114ccefbe5SStefano Stabellini 124ccefbe5SStefano Stabellini #include <xen/events.h> 134ccefbe5SStefano Stabellini #include <xen/features.h> 144ccefbe5SStefano Stabellini #include <xen/interface/xen.h> 154ccefbe5SStefano Stabellini #include <xen/interface/vcpu.h> 164ccefbe5SStefano Stabellini #include <xen/xen-ops.h> 174ccefbe5SStefano Stabellini 184ccefbe5SStefano Stabellini /* runstate info updated by Xen */ 194ccefbe5SStefano Stabellini static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate); 204ccefbe5SStefano Stabellini 214ccefbe5SStefano Stabellini /* return an consistent snapshot of 64-bit time/counter value */ 224ccefbe5SStefano Stabellini static u64 get64(const u64 *p) 234ccefbe5SStefano Stabellini { 244ccefbe5SStefano Stabellini u64 ret; 254ccefbe5SStefano Stabellini 264ccefbe5SStefano Stabellini if (BITS_PER_LONG < 64) { 274ccefbe5SStefano Stabellini u32 *p32 = (u32 *)p; 282dd887e3SStefano Stabellini u32 h, l, h2; 294ccefbe5SStefano Stabellini 304ccefbe5SStefano Stabellini /* 314ccefbe5SStefano Stabellini * Read high then low, and then make sure high is 324ccefbe5SStefano Stabellini * still the same; this will only loop if low wraps 334ccefbe5SStefano Stabellini * and carries into high. 344ccefbe5SStefano Stabellini * XXX some clean way to make this endian-proof? 354ccefbe5SStefano Stabellini */ 364ccefbe5SStefano Stabellini do { 372dd887e3SStefano Stabellini h = READ_ONCE(p32[1]); 382dd887e3SStefano Stabellini l = READ_ONCE(p32[0]); 392dd887e3SStefano Stabellini h2 = READ_ONCE(p32[1]); 402dd887e3SStefano Stabellini } while(h2 != h); 414ccefbe5SStefano Stabellini 424ccefbe5SStefano Stabellini ret = (((u64)h) << 32) | l; 434ccefbe5SStefano Stabellini } else 442dd887e3SStefano Stabellini ret = READ_ONCE(*p); 454ccefbe5SStefano Stabellini 464ccefbe5SStefano Stabellini return ret; 474ccefbe5SStefano Stabellini } 484ccefbe5SStefano Stabellini 494ccefbe5SStefano Stabellini /* 504ccefbe5SStefano Stabellini * Runstate accounting 514ccefbe5SStefano Stabellini */ 524ccefbe5SStefano Stabellini void xen_get_runstate_snapshot(struct vcpu_runstate_info *res) 534ccefbe5SStefano Stabellini { 544ccefbe5SStefano Stabellini u64 state_time; 554ccefbe5SStefano Stabellini struct vcpu_runstate_info *state; 564ccefbe5SStefano Stabellini 574ccefbe5SStefano Stabellini BUG_ON(preemptible()); 584ccefbe5SStefano Stabellini 594ccefbe5SStefano Stabellini state = this_cpu_ptr(&xen_runstate); 604ccefbe5SStefano Stabellini 614ccefbe5SStefano Stabellini /* 624ccefbe5SStefano Stabellini * The runstate info is always updated by the hypervisor on 634ccefbe5SStefano Stabellini * the current CPU, so there's no need to use anything 644ccefbe5SStefano Stabellini * stronger than a compiler barrier when fetching it. 654ccefbe5SStefano Stabellini */ 664ccefbe5SStefano Stabellini do { 674ccefbe5SStefano Stabellini state_time = get64(&state->state_entry_time); 682dd887e3SStefano Stabellini *res = READ_ONCE(*state); 694ccefbe5SStefano Stabellini } while (get64(&state->state_entry_time) != state_time); 704ccefbe5SStefano Stabellini } 714ccefbe5SStefano Stabellini 724ccefbe5SStefano Stabellini /* return true when a vcpu could run but has no real cpu to run on */ 734ccefbe5SStefano Stabellini bool xen_vcpu_stolen(int vcpu) 744ccefbe5SStefano Stabellini { 754ccefbe5SStefano Stabellini return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable; 764ccefbe5SStefano Stabellini } 774ccefbe5SStefano Stabellini 784ccefbe5SStefano Stabellini void xen_setup_runstate_info(int cpu) 794ccefbe5SStefano Stabellini { 804ccefbe5SStefano Stabellini struct vcpu_register_runstate_memory_area area; 814ccefbe5SStefano Stabellini 824ccefbe5SStefano Stabellini area.addr.v = &per_cpu(xen_runstate, cpu); 834ccefbe5SStefano Stabellini 844ccefbe5SStefano Stabellini if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area, 854ccefbe5SStefano Stabellini cpu, &area)) 864ccefbe5SStefano Stabellini BUG(); 874ccefbe5SStefano Stabellini } 884ccefbe5SStefano Stabellini 89