Re: [PATCH v6 13/60] i386/tdx: Validate TD attributes

[Xiaoyao Li]

On 11/6/2024 4:56 AM, Edgecombe, Rick P wrote:
> On Tue, 2024-11-05 at 01:23 -0500, Xiaoyao Li wrote:
> > -static void setup_td_guest_attributes(X86CPU *x86cpu)
> > +static int tdx_validate_attributes(TdxGuest *tdx, Error **errp)
> > +{
> > +    if ((tdx->attributes & ~tdx_caps->supported_attrs)) {
> > +            error_setg(errp, "Invalid attributes 0x%lx for TDX VM "
> > +                       "(supported: 0x%llx)",
> > +                       tdx->attributes, tdx_caps->supported_attrs);
> > +            return -1;
> > +    }
> > +
> > +    if (tdx->attributes & TDX_TD_ATTRIBUTES_DEBUG) {
>
> What is going on here? It doesn't look like debug attribute could be set in this
> series, so this is dead code I guess. If there is some concern that attributes
> that need extra qemu support could be set in QEMU somehow, it would be better to
> have a mask of qemu supported attributes and reject any not in the mask.

Good catch and good idea!

Will maintain a mask of supported attributes in QEMU.

> > +        error_setg(errp, "Current QEMU doesn't support attributes.debug[bit 0] 
> > "
> > +                         "for TDX VM");
> > +        return -1;
> > +    }
> > +
> > +    return 0;
> > +}