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Date:   Tue, 27 Feb 2018 15:58:10 +0100
From:   Cornelia Huck <cohuck@redhat.com>
To:     Tony Krowiak <akrowiak@linux.vnet.ibm.com>
Cc:     linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, freude@de.ibm.com, schwidefsky@de.ibm.com,
        heiko.carstens@de.ibm.com, borntraeger@de.ibm.com,
        kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com,
        pbonzini@redhat.com, alex.williamson@redhat.com,
        pmorel@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com,
        mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com,
        thuth@redhat.com, pasic@linux.vnet.ibm.com,
        fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com
Subject: Re: [PATCH v2 00/15] s390: vfio-ap: guest dedicated crypto adapters
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On Tue, 27 Feb 2018 09:27:58 -0500
Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:

> 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.
> 
> v1 => v2 Change log:
> ===================

Uh, this is very long... It seems most of the changes are not related
to the basic approach, but concerned with details? The general
structure was fine last time IIRC.

> * Added documentation vfio-ap.txt
> * Renamed vfio_ap_matrix module and device driver to vfio_ap
> * Use device core device list instead of maintaining list of matrix
>   devices in driver
> * Added VSIE support for AP
> * Create matrix device before registering VFIO AP device driver with the
>   AP bus
> * Renamed the following files in drivers/s390/crypto:
>   * vfio_ap_matrix.drv -> vfio_ap_drv
>   * vfio_ap_matrix_private.h -> vfio_ap_private.h
>   * vfio_ap_matrix_ops.c -> vfio_ap_ops.c
> * arch/s390/include/asm/kvm/ap-matrix-config.h
>   * Renamed to kvm-ap.h
>   * Changed the data type of the bit mask fields for the matrix structure
>     to unsigned long and create them with DECLARE_BITMAP 
>   * Changed #define prefixes from AP_MATRIX to KVM_AP
>   * Changed function and structure prefixes from ap_matrix to kvm_ap
>   * Added function interface to check if AP Extended Addressing (APXA)
>     facility is installedCRYCB_FORMAT_MASK
>   * Added function interface to get the maximum ID for AP mask type
>   * Added function interface to set the AP execution mode
> * arch/s390/kvm/ap-matrix-config.c
>   * Renamed to kvm-ap.c
>   * Changed function prefixes from ap_matrix to kvm_ap
>   * Added function to check if AP Extended Addressing (APXA) facility is
>     installed
>   * Added function to get the maximum ID for AP mask type
>   * Added function to set the AP execution mode
>   * Added a boolean parameter to the functions that retrieve the APM, AQM
>     and ADM bit mask fields from the CRYCB. If true, then the function
>     will clear the bits in the mask before returning a reference to it
>   * Added validation to verify that APM, AQM and ADM bits that are set do
>     not exceed the maximum ID value allowed
>   * 
> * arch/s390/include/asm/kvm_host.h
>   * Changed defined for ECA_AP to ECA_APIE - interpretive execution mode
>   * Added a flag to struct kvm_s390_crypto to indicate whether the 
>     KVM_S390_VM_CPU_FEAT_AP CPU model feature for AP facilities is set
>   * Added two CPU facilities features to set STFLE.12 and STFLE.15
> * arch/s390/kvm/kvm-s390.c
>   * Added initialization for new KVM_S390_VM_CPU_FEAT_AP CPU model feature
>   * Removed kvm_s390_apxa_installed() function
>   * Changed call to kvm_s390_apxa_installed() which has been removed to a
>     call to new kvm_ap_apxa_installed() function.
>   * Added code to kvm_s390_vcpu_crypto_setup() to set the new CPU model 
>     feature flag in the kvm_s390_crypto structure 
>   * Added CRYCB_FORMAT_MASK to mask CRYCBD
> * arch/s390/tools/gen_facilities.c
>   * Added STFLE.12 and STFLE.15 to struct facility _def
> * drivers/s390/crypto/vfio_ap_matrix_private.h
>   * Changed name of file to vfio_ap.private.h
>   * Changed #define prefixes from VFIO_AP_MATRIX to VFIO_AP
>   * struct ap_matrix: removed list fields and locks
>   * struct vfio_ap_queue: removed list field
>   * Renamed functions ap_matrix_mdev_register and ap_matrix_mdev_unregister
>     to vfio_ap_mdev_register and vfio_ap_mdev_unregister respectively
> * drivers/s390/crypto/vfio_ap_matrix_drv.c
>   * Renamed file to drivers/s390/crypto/vfio_ap_drv.c
>   * Changed all #define, structure and function prefixes to vfio_ap
>   * probe function
>     * Changed root device name for the matrix device to vfio_ap:
>       i.e., /sys/devices/vfio_ap/matrix
>     * No longer storing the AP queue device in a list, it is retrievable 
>       via the device core
>     * Removed unnecessary check whether matrix device exists
>     * Store the vfio_ap_queue structure in the private field of the 
>       ap_queue structure rather than using list interface
>   * remove function
>     * Retrieve vfio_ap_queue structure from the struct ap_queue private 
>       data rather than from a list
>   * Removed unnecessary check 
> * drivers/s390/crypto/vfio_ap_matrix_ops.c
>   * Renamed file to vfio_ap_ops.c
>   * Changed #define prefixes from AP_MATRIX to VFIO_AP
>   * Changed function name prefixes from ap_matrix to vfio_ap
>   * Removed ioctl to configure the CRYCB
>   * create function
>     * Removed ap_matrix_mdev_find_by_uuid() function - function is provided
>       by mdev core
>     * Removed available_instances verification, provided by mdev core
>     * Removed check to see if mediated device exists, handled by mdev core
>   * notifier function
>     * Configuring matrix here instead of via ioctl
>     * Set interpretive execution mode for all VCPUs
>    * Removed R/O attributes to display adapters and domains
>    * Added an R/O attribute to display the matrix
>   * assign_control_domain mdev attribute:
>     * Removed check to see if the domain is installed on the linux host
>     * Added check to verify the control domain ID does not exceed the max 
>       value
>   * assign_adapter mdev attribute:
>     * Added check to verify the adapter ID does not exceed the max 
>       value
>     * If any APQNs configured for the mediated matrix device that
>       have an APID matching the adapter ID being assigned are not
>       bound to the vfio_ap device driver then it is assumed that the APQN 
>       is bound to another driver and assignment will fail
>   * assign_domain mdev attribute:
>     * Added check to verify the domain ID does not exceed the max 
>       value
>     * If any APQNs configured for the mediated matrix device that
>       have an APQI matching the domain ID being assigned are not
>       bound to the vfio_ap device driver then it is assumed that the APQN 
>       is bound to another driver and assignment will fail
> * tools/arch/s390/include/uapi/asm/kvm.h
>   * removed  KVM_S390_VM_CPU_FEAT_AP feature definition
> 
> Tony Krowiak (15):
>   KVM: s390: refactor crypto initialization
>   s390: vsie: implement AP support for second level guest
>   s390: zcrypt: externalize AP instructions available function
>   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 configure/deconfigure guest's AP matrix
>   KVM: s390: interface to enable AP execution mode
>   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 CRYCB
>   s390: vfio-ap: implement VFIO_DEVICE_GET_INFO ioctl
>   s390: doc: detailed specifications for AP virtualization
> 
>  Documentation/s390/vfio-ap.txt          |  514 ++++++++++++++++++
>  MAINTAINERS                             |   14 +
>  arch/s390/Kconfig                       |    8 +
>  arch/s390/configs/default_defconfig     |    3 +
>  arch/s390/configs/gcov_defconfig        |    3 +
>  arch/s390/configs/performance_defconfig |    3 +
>  arch/s390/defconfig                     |    3 +
>  arch/s390/include/asm/ap.h              |    7 +
>  arch/s390/include/asm/kvm-ap.h          |   59 +++
>  arch/s390/include/asm/kvm_host.h        |    2 +
>  arch/s390/include/uapi/asm/kvm.h        |    1 +
>  arch/s390/kvm/Makefile                  |    2 +-
>  arch/s390/kvm/kvm-ap.c                  |  336 ++++++++++++
>  arch/s390/kvm/kvm-s390.c                |   66 +--
>  arch/s390/kvm/kvm-s390.h                |    1 +
>  arch/s390/kvm/vsie.c                    |   71 +++-
>  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       |  868 +++++++++++++++++++++++++++++++
>  drivers/s390/crypto/vfio_ap_private.h   |   45 ++
>  include/uapi/linux/vfio.h               |    2 +
>  23 files changed, 2096 insertions(+), 67 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
>