Re: [PATCH v19 109/130] KVM: TDX: Handle TDX PV port io hypercall

Isaku Yamahata
2024-04-17T20:11:12Z

On Wed, Apr 17, 2024 at 08:51:39PM +0800,
Binbin Wu <binbin.wu@linux.intel.com> wrote:

>
>
> On 2/26/2024 4:26 PM, isaku.yamahata@intel.com wrote:
> > From: Isaku Yamahata <isaku.yamahata@intel.com>
> >
> > Wire up TDX PV port IO hypercall to the KVM backend function.
> >
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> > ---
> > v18:
> > - Fix out case to set R10 and R11 correctly when user space handled port
> > out.
> > ---
> > arch/x86/kvm/vmx/tdx.c | 67 ++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 67 insertions(+)
> >
> > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> > index a2caf2ae838c..55fc6cc6c816 100644
> > --- a/arch/x86/kvm/vmx/tdx.c
> > +++ b/arch/x86/kvm/vmx/tdx.c
> > @@ -1152,6 +1152,71 @@ static int tdx_emulate_hlt(struct kvm_vcpu *vcpu)
> > return kvm_emulate_halt_noskip(vcpu);
> > }
> > +static int tdx_complete_pio_out(struct kvm_vcpu *vcpu)
> > +{
> > + tdvmcall_set_return_code(vcpu, TDVMCALL_SUCCESS);
> > + tdvmcall_set_return_val(vcpu, 0);
> > + return 1;
> > +}
> > +
> > +static int tdx_complete_pio_in(struct kvm_vcpu *vcpu)
> > +{
> > + struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt;
> > + unsigned long val = 0;
> > + int ret;
> > +
> > + WARN_ON_ONCE(vcpu->arch.pio.count != 1);
> > +
> > + ret = ctxt->ops->pio_in_emulated(ctxt, vcpu->arch.pio.size,
> > + vcpu->arch.pio.port, &val, 1);
> > + WARN_ON_ONCE(!ret);
> > +
> > + tdvmcall_set_return_code(vcpu, TDVMCALL_SUCCESS);
> > + tdvmcall_set_return_val(vcpu, val);
> > +
> > + return 1;
> > +}
> > +
> > +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);
> > + port = tdvmcall_a2_read(vcpu);
> > +
> > + if (size != 1 && size != 2 && size != 4) {
> > + tdvmcall_set_return_code(vcpu, TDVMCALL_INVALID_OPERAND);
> > + return 1;
> > + }
> > +
> > + if (write) {
> > + val = tdvmcall_a3_read(vcpu);
> > + ret = ctxt->ops->pio_out_emulated(ctxt, size, port, &val, 1);
> > +
> > + /* No need for a complete_userspace_io callback. */
> I am confused about the comment.
>
> The code below sets the complete_userspace_io callback for write case,
> i.e. tdx_complete_pio_out().

You're correct. This comment is stale and should be removed it.
--
Isaku Yamahata <isaku.yamahata@intel.com>