linux-kernel - [PATCH v5 00/13] s390: vfio-ap: guest dedicated crypto adapters

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Date:   Mon,  7 May 2018 11:11:39 -0400
From:   Tony Krowiak <akrowiak@...ux.vnet.ibm.com>
To:     linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     freude@...ibm.com, schwidefsky@...ibm.com,
        heiko.carstens@...ibm.com, borntraeger@...ibm.com,
        cohuck@...hat.com, kwankhede@...dia.com,
        bjsdjshi@...ux.vnet.ibm.com, pbonzini@...hat.com,
        alex.williamson@...hat.com, pmorel@...ux.vnet.ibm.com,
        alifm@...ux.vnet.ibm.com, mjrosato@...ux.vnet.ibm.com,
        jjherne@...ux.vnet.ibm.com, thuth@...hat.com,
        pasic@...ux.vnet.ibm.com, berrange@...hat.com,
        fiuczy@...ux.vnet.ibm.com, buendgen@...ibm.com,
        akrowiak@...ux.vnet.ibm.com
Subject: [PATCH v5 00/13] s390: vfio-ap: guest dedicated crypto adapters

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.

v4 => v5 Change log:
===================
* Added code to mdev open callback to ensure not more than one vfio-ap
  device can be opened by a guest.
* Interpret AP instructions by default
* Removed patch implementing interface to enable/disable AP interpretation,
  since that will now be done by default
* Removed patch to reset crypto attributes for ALL vcpus. That will be 
  submitted as a single patch since it will not be needed in this series - 
  i.e., it was called from the interface to enable/disable AP instructions
* All code for initializing crypto for a guest has been moved back to 
  kvm-s390.c, kvm_s390_crypto_init(kvm) function
* Maintaining a module reference count for the vfio_ap module so it is not
  removed while a guest with AP devices is running.
* AP bus interfaces needed by KVM that are unavailable if CONFIG_ZCRYPT=n
  are temporarily embedded in KVM until available statically via future 
  patch.


Tony Krowiak (13):
  KVM: s390: Interface to test whether APXA installed
  KVM: s390: refactor crypto initialization
  KVM: s390: CPU model support for AP virtualization
  s390: vfio-ap: base implementation of VFIO AP device driver
  s390: vfio-ap: register matrix device with VFIO mdev framework
  KVM: s390: interfaces to manage 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: implement mediated device open callback
  s390: vfio-ap: implement VFIO_DEVICE_GET_INFO ioctl
  s390: doc: detailed specifications for AP virtualization

 Documentation/s390/vfio-ap.txt        |  575 +++++++++++++++++++++
 MAINTAINERS                           |   13 +
 arch/s390/Kconfig                     |   11 +
 arch/s390/include/asm/kvm-ap.h        |  133 +++++
 arch/s390/include/asm/kvm_host.h      |    5 +
 arch/s390/include/uapi/asm/kvm.h      |    1 +
 arch/s390/kvm/Makefile                |    2 +-
 arch/s390/kvm/kvm-ap.c                |  263 ++++++++++
 arch/s390/kvm/kvm-s390.c              |  116 +++---
 arch/s390/tools/gen_facilities.c      |    3 +
 drivers/s390/crypto/Makefile          |    4 +
 drivers/s390/crypto/vfio_ap_drv.c     |  143 ++++++
 drivers/s390/crypto/vfio_ap_ops.c     |  906 +++++++++++++++++++++++++++++++++
 drivers/s390/crypto/vfio_ap_private.h |   76 +++
 include/uapi/linux/vfio.h             |    2 +
 15 files changed, 2194 insertions(+), 59 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