Commit e5e57e7a authored by Paolo Bonzini's avatar Paolo Bonzini

kvm: x86: only channel 0 of the i8254 is linked to the HPET

While setting the KVM PIT counters in 'kvm_pit_load_count', if
'hpet_legacy_start' is set, the function disables the timer on
channel[0], instead of the respective index 'channel'. This is
because channels 1-3 are not linked to the HPET.  Fix the caller
to only activate the special HPET processing for channel 0.
Reported-by: default avatarP J P <>
Fixes: 0185604cSigned-off-by: default avatarPaolo Bonzini <>
parent 16830985
......@@ -420,6 +420,7 @@ void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_s
u8 saved_mode;
if (hpet_legacy_start) {
/* save existing mode for later reenablement */
WARN_ON(channel != 0);
saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
pit_load_count(kvm, channel, val);
......@@ -3606,7 +3606,8 @@ static int kvm_vm_ioctl_set_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
kvm->arch.vpit->pit_state.flags = ps->flags;
for (i = 0; i < 3; i++)
kvm_pit_load_count(kvm, i, kvm->arch.vpit->pit_state.channels[i].count, start);
kvm_pit_load_count(kvm, i, kvm->arch.vpit->pit_state.channels[i].count,
start && i == 0);
return 0;
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