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KVM: PIT: control word is write-only

PATCH Marcelo Tosatti 2 participants 2 messages Jan 29, 2010 – Feb 1, 2010

Subsystems (3)
x86 KVM KVM x86
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Marcelo Tosatti

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PIT control word (address 0x43) is write-only, reads are undefined.

Cc [email protected]
Signed-off-by Marcelo Tosatti <[email protected]>
arch/x86/kvm/i8254.c +3 -0
index caad189..6a74246 100644
@@ -467,6 +467,9 @@ static int pit_ioport_read(struct kvm_io_device *this,
 		return -EOPNOTSUPP;
 
 	addr &= KVM_PIT_CHANNEL_MASK;
+	if (addr == 3)
+		return 0;
+
 	s = &pit_state->channels[addr];
 
 	mutex_lock(&pit_state->lock);