Re: [PATCH v5 09/11] x86/domctl: add XEN_DOMCTL_vmtrace_op

[Julien Grall <julien@xxxxxxx>]

On 06/07/2020 11:37, Jan Beulich wrote:
> On 06.07.2020 12:31, Julien Grall wrote:
> > On 05/07/2020 19:55, Michał Leszczyński wrote:
> > > +/* XEN_DOMCTL_vmtrace_op: Perform VM tracing related operation */
> > > +#if defined(__XEN__) || defined(__XEN_TOOLS__)
> > > +
> > > +struct xen_domctl_vmtrace_op {
> > > +    /* IN variable */
> > > +    uint32_t cmd;
> > > +/* Enable/disable external vmtrace for given domain */
> > > +#define XEN_DOMCTL_vmtrace_pt_enable      1
> > > +#define XEN_DOMCTL_vmtrace_pt_disable     2
> > > +#define XEN_DOMCTL_vmtrace_pt_get_offset  3
> > > +    domid_t domain;
> > AFAICT, there is a 16-bit implicit padding here and ...
> >
> >
> > > +    uint32_t vcpu;
> > ... a 32-bit implicit padding here. I would suggest to make
> > the two explicit.
> >
> > We possibly want to check they are also always zero.
> Not just possibly imo - we should.
I wasn't sure given that DOMCTL is not a stable interface.

Cheers,

--
Julien Grall