kbase: Document how to disable Secure Boot entirely

In most cases, disabling the secure-boot or the enrolled-keys
firmware feature will achieve the same result: allowing an
unsigned operating system to run.

Right now we're only documenting the latter configuration. Add
the former as well, and explain the difference between the two.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Andrea Bolognani 2022-08-04 10:43:09 +02:00
parent 18249f278a
commit 550bf7682d

View File

@ -19,7 +19,17 @@ ask for Secure Boot to be enabled with
</firmware>
</os>
and for it to be disabled with
and for it to be disabled with either
::
<os firmware='efi'>
<firmware>
<feature enabled='no' name='secure-boot'/>
</firmware>
</os>
or
::
@ -30,8 +40,10 @@ and for it to be disabled with
</firmware>
</os>
These configuration will cause unsigned guest operating systems to
be rejected and allowed respectively.
The first configuration will cause unsigned guest operating systems
to be rejected, while the remaining two will allow running them. See
below for a more detailed explanation of how each knob affects the
firmware selection process.
Older libvirt versions
@ -103,3 +115,16 @@ The opposite configuration, where the feature is explicitly disabled,
will result in no keys being present in the NVRAM file. Unable to
verify signatures, the firmware will allow even unsigned operating
systems to run.
If running unsigned code is desired, it's also possible to ask for
the ``secure-boot`` feature to be disabled, which will cause libvirt
to pick a build of EDKII that doesn't have Secure Boot support at
all.
The main difference between using a build of EDKII that has Secure
Boot support but without keys enrolled and one that doesn't have
Secure Boot support at all is that, with the former, you could enroll
your own keys and securely run an operating system that you've built
and signed yourself. If you are only planning to run existing,
off-the-shelf operating system images, then the two configurations
are functionally equivalent.