[PATCH v4 00/15] s390: vfio-ap: guest dedicated crypto adapters

Tony Krowiak
2018-04-15T21:22:10Z

On s390, we have cryptographic coprocessor cards, which are modeled on
Linux as devices on the AP bus. Each card can be partitioned into domains
which can be thought of as a set of hardware registers for processing
crypto commands. Crypto commands are sent to a specific domain within a
card is via a queue which is identified as a (card,domain) tuple. We model
this something like the following (assuming we have access to cards 3 and
4 and domains 1 and 2):

AP -> card3 -> queue (3,1)
-> queue (3,2)
-> card4 -> queue (4,1)
-> queue (4,2)

If we want to virtualize this, we can use a feature provided by the
hardware. We basically attach a satellite control block to our main
hardware virtualization control block and the hardware takes care of
most of the rest.

For this control block, we don't specify explicit tuples, but a list of
cards and a list of domains. The guest will get access to the cross
product.

Because of this, we need to take care that the lists provided to
different guests don't overlap; i.e., we need to enforce sane
configurations. Otherwise, one guest may get access to things like
secret keys for another guest.

The idea of this patch set is to introduce a new device, the matrix
device. This matrix device hangs off a different root and acts as the
parent node for mdev devices.

If you now want to give the tuples (4,1) and (4,2), you need to do the
following:

- Unbind the (4,1) and (4,2) tuples from their ap bus driver.
- Bind the (4,1) and (4,2) tuples to the vfio_ap driver.
- Create the mediated device.
- Assign card 4 and domains 1 and 2 to the mediated device

QEMU will now simply consume the mediated device and things should work.

For a complete description of the architecture and concepts underlying the
design, see the Documentation/s390/vfio-ap.txt file included with this
patch set.

Change log v3 -> v4
===================
* Resolved issue with enabling ZCRYPT when KVM is enabled by using
#ifdef ZCRYPT in relevant functions
* Added patch with a new function for resetting the crypto attributes
for all vcpus to resolve the issue raised with running vcpus getting out
of sync.
* Removed KVM_S390_VM_CRYPTO_INTERPRET_AP: Setting interpretive exec mode
from vfio_ap driver when mdev device is opened.

Tony Krowiak (15):
s390: zcrypt: externalize AP instructions available function
KVM: s390: reset crypto attributes for all vcpus
KVM: s390: refactor crypto initialization
KVM: s390: CPU model support for AP virtualization
KVM: s390: enable/disable AP interpretive execution
s390: vfio-ap: base implementation of VFIO AP device driver
s390: vfio-ap: register matrix device with VFIO mdev framework
KVM: s390: interfaces to (de)configure guest's AP matrix
s390: vfio-ap: sysfs interfaces to configure adapters
s390: vfio-ap: sysfs interfaces to configure domains
s390: vfio-ap: sysfs interfaces to configure control domains
s390: vfio-ap: sysfs interface to view matrix mdev matrix
KVM: s390: configure the guest's AP devices
s390: vfio-ap: implement VFIO_DEVICE_GET_INFO ioctl
s390: doc: detailed specifications for AP virtualization

Documentation/s390/vfio-ap.txt | 567 +++++++++++++++++++++
MAINTAINERS | 12 +
arch/s390/Kconfig | 11 +
arch/s390/include/asm/ap.h | 7 +
arch/s390/include/asm/kvm-ap.h | 136 +++++
arch/s390/include/asm/kvm_host.h | 3 +
arch/s390/include/uapi/asm/kvm.h | 1 +
arch/s390/kvm/Makefile | 2 +-
arch/s390/kvm/kvm-ap.c | 339 +++++++++++++
arch/s390/kvm/kvm-s390.c | 93 ++---
arch/s390/kvm/kvm-s390.h | 14 +
arch/s390/tools/gen_facilities.c | 2 +
drivers/s390/crypto/Makefile | 4 +
drivers/s390/crypto/ap_bus.c | 6 +
drivers/s390/crypto/vfio_ap_drv.c | 143 ++++++
drivers/s390/crypto/vfio_ap_ops.c | 873 +++++++++++++++++++++++++++++++++
drivers/s390/crypto/vfio_ap_private.h | 46 ++
include/uapi/linux/vfio.h | 2 +
18 files changed, 2200 insertions(+), 61 deletions(-)
create mode 100644 Documentation/s390/vfio-ap.txt
create mode 100644 arch/s390/include/asm/kvm-ap.h
create mode 100644 arch/s390/kvm/kvm-ap.c
create mode 100644 drivers/s390/crypto/vfio_ap_drv.c
create mode 100644 drivers/s390/crypto/vfio_ap_ops.c
create mode 100644 drivers/s390/crypto/vfio_ap_private.h