Harald Freudenberger 78f636e82b s390/ap: Fix CCA crypto card behavior within protected execution environment
A crypto card comes in 3 flavors: accelerator, CCA co-processor or
EP11 co-processor. Within a protected execution environment only the
accelerator and EP11 co-processor is supported. However, it is
possible to set up a KVM guest with a CCA card and run it as a
protected execution guest. There is nothing at the host side which
prevents this. Within such a guest, a CCA card is shown as "illicit"
and you can't do anything with such a crypto card.

Regardless of the unsupported CCA card within a protected execution
guest there are a couple of user space applications which
unconditional try to run crypto requests to the zcrypt device
driver. There was a bug within the AP bus code which allowed such a
request to be forwarded to a CCA card where it is finally
rejected and the driver reacts with -ENODEV but also triggers an AP
bus scan. Together with a retry loop this caused some kind of "hang"
of the KVM guest. On startup it caused timeouts and finally led the
KVM guest startup fail. Fix that by closing the gap and make sure a
CCA card is not usable within a protected execution environment.

Another behavior within an protected execution environment with CCA
cards was that the se_bind and se_associate AP queue sysfs attributes
where shown. The implementation unconditional always added these
attributes. Fix that by checking if the card mode is supported within
a protected execution environment and only if valid, add the attribute
group.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-10-10 15:31:55 +02:00
..
2022-04-25 13:54:14 +02:00