Virtualization - Nov 2021 - [PATCH v2 01/12] kexec: Allow architecture code to opt-out at runtime

On Mon, Sep 13, 2021 at 05:55:52PM +0200, Joerg Roedel
wrote:
> From: Joerg Roedel <jroedel at suse.de>
> 
> Allow a runtime opt-out of kexec support for architecture code in case
> the kernel is running in an environment where kexec is not properly
> supported yet.
> 
> This will be used on x86 when the kernel is running as an SEV-ES
> guest. SEV-ES guests need special handling for kexec to hand over all
> CPUs to the new kernel. This requires special hypervisor support and
> handling code in the guest which is not yet implemented.
> 
> Cc: stable at vger.kernel.org # v5.10+
> Signed-off-by: Joerg Roedel <jroedel at suse.de>
> ---
>  include/linux/kexec.h |  1 +
>  kernel/kexec.c        | 14 ++++++++++++++
>  kernel/kexec_file.c   |  9 +++++++++
>  3 files changed, 24 insertions(+)
I guess I can take this through the tip tree along with the next one.

Eric?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Borislav Petkov <bp at alien8.de> writes:
> On Mon, Sep 13, 2021 at 05:55:52PM +0200, Joerg Roedel wrote:
>> From: Joerg Roedel <jroedel at suse.de>
>> 
>> Allow a runtime opt-out of kexec support for architecture code in case
>> the kernel is running in an environment where kexec is not properly
>> supported yet.
>> 
>> This will be used on x86 when the kernel is running as an SEV-ES
>> guest. SEV-ES guests need special handling for kexec to hand over all
>> CPUs to the new kernel. This requires special hypervisor support and
>> handling code in the guest which is not yet implemented.
>> 
>> Cc: stable at vger.kernel.org # v5.10+
>> Signed-off-by: Joerg Roedel <jroedel at suse.de>
>> ---
>>  include/linux/kexec.h |  1 +
>>  kernel/kexec.c        | 14 ++++++++++++++
>>  kernel/kexec_file.c   |  9 +++++++++
>>  3 files changed, 24 insertions(+)
>
> I guess I can take this through the tip tree along with the next one.
I seem to remember the consensus when this was reviewed that it was
unnecessary and there is already support for doing something like
this at a more fine grained level so we don't need a new kexec hook.

Eric