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 "device_tree.h"
  18
  19 #define PROC_DEVTREE_PATH "/proc/device-tree"
  20
  21 static QEMUTimer *kvmppc_timer;
  22 static unsigned int kvmppc_timer_rate;
  23
  24 static void kvmppc_timer_hack(void *opaque)
  25 {
  26     qemu_notify_event();
  27     qemu_mod_timer(kvmppc_timer, qemu_get_clock_ns(vm_clock) + kvmppc_timer_rate);
  28 }
  29
  30 void kvmppc_init(void)
  31 {
  32     /* XXX The only reason KVM yields control back to qemu is device IO. Since
  33      * an idle guest does no IO, qemu's device model will never get a chance to
  34      * run. So, until Qemu gains IO threads, we create this timer to ensure
  35      * that the device model gets a chance to run. */
  36     kvmppc_timer_rate = get_ticks_per_sec() / 10;
  37     kvmppc_timer = qemu_new_timer_ns(vm_clock, &kvmppc_timer_hack, NULL);
  38     qemu_mod_timer(kvmppc_timer, qemu_get_clock_ns(vm_clock) + kvmppc_timer_rate);
  39 }
  40