On Thu, Apr 07, 2022, Paolo Bonzini wrote:
> On 3/4/22 20:49, isaku.yamahata@xxxxxxxxx wrote:
> > From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> >
> > Wire up TDX PV CPUID hypercall to the KVM backend function.
> >
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> > ---
> > arch/x86/kvm/vmx/tdx.c | 27 +++++++++++++++++++++++++++
> > 1 file changed, 27 insertions(+)
> >
> > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> > index 53f59fb92dcf..f7c9170d596a 100644
> > --- a/arch/x86/kvm/vmx/tdx.c
> > +++ b/arch/x86/kvm/vmx/tdx.c
> > @@ -893,6 +893,30 @@ static int tdx_emulate_vmcall(struct kvm_vcpu *vcpu)
> > return 1;
> > }
> > +static int tdx_emulate_cpuid(struct kvm_vcpu *vcpu)
> > +{
> > + u32 eax, ebx, ecx, edx;
> > +
> > + /* EAX and ECX for cpuid is stored in R12 and R13. */
> > + eax = tdvmcall_p1_read(vcpu);
> > + ecx = tdvmcall_p2_read(vcpu);
> > +
> > + kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, true);
> > +
> > + /*
> > + * The returned value for CPUID (EAX, EBX, ECX, and EDX) is stored into
> > + * R12, R13, R14, and R15.
> > + */
> > + tdvmcall_p1_write(vcpu, eax);
> > + tdvmcall_p2_write(vcpu, ebx);
> > + tdvmcall_p3_write(vcpu, ecx);
> > + tdvmcall_p4_write(vcpu, edx);
> > +
> > + tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_SUCCESS);
> > +
> > + return 1;
> > +}
> > +
> > static int handle_tdvmcall(struct kvm_vcpu *vcpu)
> > {
> > struct vcpu_tdx *tdx = to_tdx(vcpu);
> > @@ -904,6 +928,9 @@ static int handle_tdvmcall(struct kvm_vcpu *vcpu)
> > return tdx_emulate_vmcall(vcpu);
> > switch (tdvmcall_exit_reason(vcpu)) {
> > + case EXIT_REASON_CPUID:
> > + return tdx_emulate_cpuid(vcpu);
> > +
Spurious whitespace that gets deleted by the HLT patch.
> > default:
> > break;
> > }
>
> Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>
> but I don't think tdvmcall_*_{read,write} add much.
They provided a lot more value when the ABI was still in flux, but I still like
having them. That said, either the comments about R12..R15 need to go, or the
wrappers need to go. Having both is confusing.
