Re: [PATCH v3] x86: svm: use kvm_fast_pio_in()

[Joel Schopp <joel.schopp@amd.com>]

On 03/03/2015 10:44 AM, Radim Krčmář wrote:
> 2015-03-02 15:02-0600, Joel Schopp:
>> +int kvm_fast_pio_in(struct kvm_vcpu *vcpu, int size, unsigned short port)
>> +{
>> +	unsigned long val;
>> +	int ret = emulator_pio_in_emulated(&vcpu->arch.emulate_ctxt, size,
>> +					   port, &val, 1);
>> +
> Btw. does this return 1 in some scenario?
If a function returns a value it is always a good idea to check it and
act appropriately.  That said...
emulator_pio_in_emulated will return 1 if emulator_pio_in_out returns 1
or if vcpu->arch.pio.count != 0
emulator_pio_in_out returns 1 if kernel_pio returns 0
kernel_pio returns 0 if kvm_io_bus_read returns 0