RE: [PATCH v2 8/8] KVM: x86: Add checks for reserved-to-zero Hyper-V hypercall fields

Michael Kelley (LINUX)
2021-12-02T15:16:54Z

From: Sean Christopherson <seanjc@google.com> Sent: Wednesday, December 1, 2021 6:13 PM
>
> On Mon, Nov 01, 2021, Vitaly Kuznetsov wrote:
> > Sean Christopherson <seanjc@google.com> writes:
> >
> > > Add checks for the three fields in Hyper-V's hypercall params that must
> > > be zero. Per the TLFS, HV_STATUS_INVALID_HYPERCALL_INPUT is returned if
> > > "A reserved bit in the specified hypercall input value is non-zero."
> > >
> > > Note, the TLFS has an off-by-one bug for the last reserved field, which
> > > it defines as being bits 64:60. The same section states "The input field
> > > 64-bit value called a hypercall input value.", i.e. bit 64 doesn't
> > > exist.
> >
> > This version are you looking at? I can't see this issue in 6.0b
>
> It's the web-based documentation, the 6.0b PDF indeed does not have the same bug.
>
> https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/hypercall-interface#hypercall-inputs

Did you (or Vitaly) file a bug report on this doc issue? If not, I can do so.

Michael