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

[Sean Christopherson]

On Mon, Nov 01, 2021, Vitaly Kuznetsov wrote:
> Sean Christopherson <seanjc@xxxxxxxxxx> 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