From e9f4275732add046fed4a548b8dbb98dbe500d2f Mon Sep 17 00:00:00 2001 From: Beth Kon Date: Tue, 7 Jul 2009 11:50:38 -0400 Subject: 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 Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/x86/kvm/i8254.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/x86/kvm/i8254.h') diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h index b2670180f225..d4c1c7ffdc09 100644 --- a/arch/x86/kvm/i8254.h +++ b/arch/x86/kvm/i8254.h @@ -21,6 +21,7 @@ struct kvm_kpit_channel_state { struct kvm_kpit_state { struct kvm_kpit_channel_state channels[3]; + u32 flags; struct kvm_timer pit_timer; bool is_periodic; u32 speaker_data_on; @@ -49,7 +50,7 @@ struct kvm_pit { #define KVM_PIT_CHANNEL_MASK 0x3 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu); -void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val); +void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start); struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags); void kvm_free_pit(struct kvm *kvm); void kvm_pit_reset(struct kvm_pit *pit); -- cgit v1.2.1