Re: [PATCH v2] SUPPORT.md: add Dom0less as Supported

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 15 Jul 2021, Julien Grall wrote:
> Hi Stefano,
> 
> On 15/07/2021 00:48, Stefano Stabellini wrote:
> > Add Dom0less to SUPPORT.md to clarify its support status. The feature is
> > mature enough and small enough to make it security supported.
> 
> I would suggest to explain the restriction in the commit message (and give a
> link to XSA-372 commit).
> 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
> > ---
> > Changes in v2:
> > - clarify memory scrubbing
> > ---
> >   SUPPORT.md | 9 +++++++++
> >   1 file changed, 9 insertions(+)
> > 
> > diff --git a/SUPPORT.md b/SUPPORT.md
> > index 317392d8f3..524cab9c8d 100644
> > --- a/SUPPORT.md
> > +++ b/SUPPORT.md
> > @@ -832,6 +832,15 @@ OVMF firmware implements the UEFI boot protocol.
> >         Status, qemu-xen: Supported
> >   +## Dom0less
> > +
> > +Guest creation from the hypervisor at boot without Dom0 intervention.
> > +
> > +    Status, ARM: Supported
> > +
> > +Memory of dom0less DomUs is not scrubbed at boot (even with
> > +bootscrub=on); no XSAs will be issues due to unscrubbed memory.
> 
> The memory will not be scrubbed for bootscrub=on and bootscrub=off. However,
> it should be scrubbed for bootscrub=idle (the default).

With bootscrub=idle, do you know if it is guaranteed to complete the
scrubbing before dom0less domUs start? I assumed it wasn't guaranteed,
but if it is, then we should rephrase the statement.