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
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