target-ppc/kvm_ppc.c

   1 /*
   2  * PowerPC KVM support
   3  *
   4  * Copyright IBM Corp. 2008
   5  *
   6  * Authors:
   7  *  Hollis Blanchard <hollisb@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu-common.h"
  15 #include "qemu/timer.h"
  16 #include "kvm_ppc.h"
  17 #include "sysemu/device_tree.h"
  18 #include "qemu/main-loop.h"
  19
  20 #define PROC_DEVTREE_PATH "/proc/device-tree"
  21
  22 static QEMUTimer *kvmppc_timer;
  23 static unsigned int kvmppc_timer_rate;
  24
  25 static void kvmppc_timer_hack(void *opaque)
  26 {
  27     qemu_notify_event();
  28     timer_mod(kvmppc_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + kvmppc_timer_rate);
  29 }
  30
  31 void kvmppc_init(void)
  32 {
  33     /* XXX The only reason KVM yields control back to qemu is device IO. Since
  34      * an idle guest does no IO, qemu's device model will never get a chance to
  35      * run. So, until QEMU gains IO threads, we create this timer to ensure
  36      * that the device model gets a chance to run. */
  37     kvmppc_timer_rate = get_ticks_per_sec() / 10;
  38     kvmppc_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &kvmppc_timer_hack, NULL);
  39     timer_mod(kvmppc_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + kvmppc_timer_rate);
  40 }
  41