path: root/virt/kvm/ioapic.c
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authorBeth Kon <eak@us.ibm.com>2009-07-07 11:50:38 -0400
committerAvi Kivity <avi@redhat.com>2009-09-10 08:33:12 +0300
commite9f4275732add046fed4a548b8dbb98dbe500d2f (patch)
tree8d9e22bbc6a9557f95712aaa98534d5983034252 /virt/kvm/ioapic.c
parent0d1de2d901f4ba0972a3886496a44fb1d3300dbd (diff)
KVM: PIT support for HPET legacy mode
When kvm is in hpet_legacy_mode, the hpet is providing the timer interrupt and the pit should not be. So in legacy mode, the pit timer is destroyed, but the *state* of the pit is maintained. So if kvm or the guest tries to modify the state of the pit, this modification is accepted, *except* that the timer isn't actually started. When we exit hpet_legacy_mode, the current state of the pit (which is up to date since we've been accepting modifications) is used to restart the pit timer. The saved_mode code in kvm_pit_load_count temporarily changes mode to 0xff in order to destroy the timer, but then restores the actual value, again maintaining "current" state of the pit for possible later reenablement. [avi: add some reserved storage in the ioctl; make SET_PIT2 IOW] [marcelo: fix memory corruption due to reserved storage] Signed-off-by: Beth Kon <eak@us.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt/kvm/ioapic.c')
0 files changed, 0 insertions, 0 deletions