Re: [PATCH 6/7] KVM: TDX: Handle TDX PV port I/O hypercall

[Binbin Wu]

On 12/10/2024 5:42 PM, Chao Gao wrote:
> > +static int tdx_emulate_io(struct kvm_vcpu *vcpu)
> > +{
> > +	struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt;
> > +	unsigned long val = 0;
> > +	unsigned int port;
> > +	int size, ret;
> > +	bool write;
> ..
>
> > +
> > +	++vcpu->stat.io_exits;
> > +
> > +	size = tdvmcall_a0_read(vcpu);
> > +	write = tdvmcall_a1_read(vcpu);
> a1 (i.e., R13) should be either 0 or 1. Other values are reserved according to
> the GHCI spec. It is not appropriate to cast it to a boolean. For example, if
> R13=2, KVM shouldn't treat it as a write request; instead, this request should
> be rejected.
Right, will fix it.

Thanks!

> > +	port = tdvmcall_a2_read(vcpu);
> > +
> > +	if (size != 1 && size != 2 && size != 4) {
> > +		tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_INVALID_OPERAND);
> > +		return 1;
> > +	}