tools/kvm/ioeventfd.c

   1 #include <sys/epoll.h>
   2 #include <sys/ioctl.h>
   3 #include <pthread.h>
   4 #include <unistd.h>
   5 #include <stdio.h>
   6 #include <signal.h>
   7
   8 #include <linux/kernel.h>
   9 #include <linux/kvm.h>
  10 #include <linux/types.h>
  11
  12 #include "kvm/ioeventfd.h"
  13 #include "kvm/kvm.h"
  14 #include "kvm/util.h"
  15
  16 #define IOEVENTFD_MAX_EVENTS    20
  17
  18 static struct   epoll_event events[IOEVENTFD_MAX_EVENTS];
  19 static int      epoll_fd;
  20 static LIST_HEAD(used_ioevents);
  21
  22 void ioeventfd__init(void)
  23 {
  24         epoll_fd = epoll_create(IOEVENTFD_MAX_EVENTS);
  25         if (epoll_fd < 0)
  26                 die("Failed creating epoll fd");
  27 }
  28
  29 void ioeventfd__add_event(struct ioevent *ioevent)
  30 {
  31         struct kvm_ioeventfd kvm_ioevent;
  32         struct epoll_event epoll_event;
  33         struct ioevent *new_ioevent;
  34         int event;
  35
  36         new_ioevent = malloc(sizeof(*new_ioevent));
  37         if (new_ioevent == NULL)
  38                 die("Failed allocating memory for new ioevent");
  39
  40         *new_ioevent = *ioevent;
  41         event = new_ioevent->fd;
  42
  43         kvm_ioevent = (struct kvm_ioeventfd) {
  44                 .addr                   = ioevent->io_addr,
  45                 .len                    = ioevent->io_len,
  46                 .datamatch              = ioevent->datamatch,
  47                 .fd                     = event,
  48                 .flags                  = KVM_IOEVENTFD_FLAG_PIO | KVM_IOEVENTFD_FLAG_DATAMATCH,
  49         };
  50
  51         if (ioctl(ioevent->fn_kvm->vm_fd, KVM_IOEVENTFD, &kvm_ioevent) != 0)
  52                 die("Failed creating new ioeventfd");
  53
  54         epoll_event = (struct epoll_event) {
  55                 .events                 = EPOLLIN,
  56                 .data.ptr               = new_ioevent,
  57         };
  58
  59         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, event, &epoll_event) != 0)
  60                 die("Failed assigning new event to the epoll fd");
  61
  62         list_add_tail(&new_ioevent->list, &used_ioevents);
  63 }
  64
  65 void ioeventfd__del_event(u64 addr, u64 datamatch)
  66 {
  67         struct kvm_ioeventfd kvm_ioevent;
  68         struct ioevent *ioevent;
  69         u8 found = 0;
  70
  71         list_for_each_entry(ioevent, &used_ioevents, list) {
  72                 if (ioevent->io_addr == addr) {
  73                         found = 1;
  74                         break;
  75                 }
  76         }
  77
  78         if (found == 0 || ioevent == NULL)
  79                 return;
  80
  81         kvm_ioevent = (struct kvm_ioeventfd) {
  82                 .addr                   = ioevent->io_addr,
  83                 .len                    = ioevent->io_len,
  84                 .datamatch              = ioevent->datamatch,
  85                 .flags                  = KVM_IOEVENTFD_FLAG_PIO
  86                                         | KVM_IOEVENTFD_FLAG_DEASSIGN
  87                                         | KVM_IOEVENTFD_FLAG_DATAMATCH,
  88         };
  89
  90         ioctl(ioevent->fn_kvm->vm_fd, KVM_IOEVENTFD, &kvm_ioevent);
  91
  92         epoll_ctl(epoll_fd, EPOLL_CTL_DEL, ioevent->fd, NULL);
  93
  94         list_del(&ioevent->list);
  95
  96         close(ioevent->fd);
  97         free(ioevent);
  98 }
  99
 100 static void *ioeventfd__thread(void *param)
 101 {
 102         for (;;) {
 103                 int nfds, i;
 104
 105                 nfds = epoll_wait(epoll_fd, events, IOEVENTFD_MAX_EVENTS, -1);
 106                 for (i = 0; i < nfds; i++) {
 107                         u64 tmp;
 108                         struct ioevent *ioevent;
 109
 110                         ioevent = events[i].data.ptr;
 111
 112                         if (read(ioevent->fd, &tmp, sizeof(tmp)) < 0)
 113                                 die("Failed reading event");
 114
 115                         ioevent->fn(ioevent->fn_kvm, ioevent->fn_ptr);
 116                 }
 117         }
 118
 119         return NULL;
 120 }
 121
 122 void ioeventfd__start(void)
 123 {
 124         pthread_t thread;
 125
 126         if (pthread_create(&thread, NULL, ioeventfd__thread, NULL) != 0)
 127                 die("Failed starting ioeventfd thread");
 128 }