KVM: Allow PIT emulation without speaker port

The in-kernel speaker emulation is only a dummy and also unneeded from
the performance point of view. Rather, it takes user space support to
generate sound output on the host, e.g. console beeps.

To allow this, introduce KVM_CREATE_PIT2 which controls in-kernel
speaker port emulation via a flag passed along the new IOCTL. It also
leaves room for future extensions of the PIT configuration interface.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 21f68e00524f..0990bc9aac1f 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -563,7 +563,7 @@ static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
         }
 }
 
-struct kvm_pit *kvm_create_pit(struct kvm *kvm)
+struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 {
         struct kvm_pit *pit;
         struct kvm_kpit_state *pit_state;
@@ -589,11 +589,13 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm)
         pit->dev.private = pit;
         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
 
-        pit->speaker_dev.read = speaker_ioport_read;
-        pit->speaker_dev.write = speaker_ioport_write;
-        pit->speaker_dev.in_range = speaker_in_range;
-        pit->speaker_dev.private = pit;
-        kvm_io_bus_register_dev(&kvm->pio_bus, &pit->speaker_dev);
+        if (flags & KVM_PIT_SPEAKER_DUMMY) {
+                pit->speaker_dev.read = speaker_ioport_read;
+                pit->speaker_dev.write = speaker_ioport_write;
+                pit->speaker_dev.in_range = speaker_in_range;
+                pit->speaker_dev.private = pit;
+                kvm_io_bus_register_dev(&kvm->pio_bus, &pit->speaker_dev);
+        }
 
         kvm->arch.vpit = pit;
         pit->kvm = kvm;