18  * @header: stats header for a vm or a vcpu
29  * |   Header    |
40  * 1. Read header from offset 0. Get the offset of descriptors and stats data
52 ssize_t kvm_stats_read(char *id, const struct kvm_stats_header *header,  in kvm_stats_read()  argument
66 	size_header = sizeof(*header);  in kvm_stats_read()
67 	size_desc = header->num_desc * sizeof(*desc);  in kvm_stats_read()
76 	 * Copy kvm stats header.  in kvm_stats_read()
77 	 * The header is the first block of content userspace usually read out.  in kvm_stats_read()
78 	 * The pos is 0 and the copylen and remain would be the size of header.  in kvm_stats_read()
79 	 * The copy of the header would be skipped if offset is larger than the  in kvm_stats_read()
80 	 * size of header. That usually happens when userspace reads stats  in kvm_stats_read()
86 		src = (void *)header + pos;  in kvm_stats_read()
95 	 * Copy kvm stats header id string.  in kvm_stats_read()
98 	 * The id string is part of the stat header from the perspective of  in kvm_stats_read()
100 	 * header part and could be skipped for later descriptors and stats  in kvm_stats_read()
103 	copylen = header->id_offset + KVM_STATS_NAME_SIZE - pos;  in kvm_stats_read()
106 		src = id + pos - header->id_offset;  in kvm_stats_read()
119 	 * (header->header.desc_offset + size_desc) causing copylen <= 0.  in kvm_stats_read()
121 	copylen = header->desc_offset + size_desc - pos;  in kvm_stats_read()
124 		src = (void *)desc + pos - header->desc_offset;  in kvm_stats_read()
133 	copylen = header->data_offset + size_stats - pos;  in kvm_stats_read()
136 		src = stats + pos - header->data_offset;  in kvm_stats_read()