Re: [PATCH v2 1/8] KVM: x86: Have ____kvm_emulate_hypercall() read the GPRs

[Binbin Wu]

On 2/11/2025 6:23 PM, Xiaoyao Li wrote:
> On 2/11/2025 10:54 AM, Binbin Wu wrote:
> > Have ____kvm_emulate_hypercall() read the GPRs instead of passing them
> > in via the macro.
> >
> > When emulating KVM hypercalls via TDVMCALL, TDX will marshall registers of
> > TDVMCALL ABI into KVM's x86 registers to match the definition of KVM
> > hypercall ABI _before_ ____kvm_emulate_hypercall() gets called. Therefore,
> > ____kvm_emulate_hypercall() can just read registers internally based on KVM
> > hypercall ABI, and those registers can be removed from the
> > __kvm_emulate_hypercall() macro.
> >
> > Also, op_64_bit can be determined inside ____kvm_emulate_hypercall(),
> > remove it from the __kvm_emulate_hypercall() macro as well.
>
> After this patch, __kvm_emulate_hypercall() becomes superfluous.
> we can just put the logic to call the "complete_hypercall" into ____kvm_emulate_hypercall() and rename it to __kvm_emulate_hypercall()
According to the commit message of
"KVM: x86: Refactor __kvm_emulate_hypercall() into a macro":
"Rework __kvm_emulate_hypercall() into a macro so that completion of
hypercalls that don't exit to userspace use direct function calls to the
completion helper, i.e. don't trigger a retpoline when RETPOLINE=y."

So I kept the macro.