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 --- include/linux/kvm.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include') diff --git a/include/linux/kvm.h b/include/linux/kvm.h index 76c640834ea6..a74a1fcc28e9 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -409,6 +409,9 @@ struct kvm_guest_debug { #define KVM_CAP_PIT2 33 #endif #define KVM_CAP_SET_BOOT_CPU_ID 34 +#ifdef __KVM_HAVE_PIT_STATE2 +#define KVM_CAP_PIT_STATE2 35 +#endif #ifdef KVM_CAP_IRQ_ROUTING @@ -586,6 +589,9 @@ struct kvm_debug_guest { #define KVM_IA64_VCPU_GET_STACK _IOR(KVMIO, 0x9a, void *) #define KVM_IA64_VCPU_SET_STACK _IOW(KVMIO, 0x9b, void *) +#define KVM_GET_PIT2 _IOR(KVMIO, 0x9f, struct kvm_pit_state2) +#define KVM_SET_PIT2 _IOW(KVMIO, 0xa0, struct kvm_pit_state2) + #define KVM_TRC_INJ_VIRQ (KVM_TRC_HANDLER + 0x02) #define KVM_TRC_REDELIVER_EVT (KVM_TRC_HANDLER + 0x03) #define KVM_TRC_PEND_INTR (KVM_TRC_HANDLER + 0x04) -- cgit v1.2.1