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Diffstat (limited to 'Documentation/arch/s390/vfio-ap.rst')
| -rw-r--r-- | Documentation/arch/s390/vfio-ap.rst | 62 |
1 files changed, 61 insertions, 1 deletions
diff --git a/Documentation/arch/s390/vfio-ap.rst b/Documentation/arch/s390/vfio-ap.rst index 929ee1c1c940..eba1991fbdba 100644 --- a/Documentation/arch/s390/vfio-ap.rst +++ b/Documentation/arch/s390/vfio-ap.rst @@ -380,6 +380,36 @@ matrix device. control_domains: A read-only file for displaying the control domain numbers assigned to the vfio_ap mediated device. + ap_config: + A read/write file that, when written to, allows all three of the + vfio_ap mediated device's ap matrix masks to be replaced in one shot. + Three masks are given, one for adapters, one for domains, and one for + control domains. If the given state cannot be set then no changes are + made to the vfio-ap mediated device. + + The format of the data written to ap_config is as follows: + {amask},{dmask},{cmask}\n + + \n is a newline character. + + amask, dmask, and cmask are masks identifying which adapters, domains, + and control domains should be assigned to the mediated device. + + The format of a mask is as follows: + 0xNN..NN + + Where NN..NN is 64 hexadecimal characters representing a 256-bit value. + The leftmost (highest order) bit represents adapter/domain 0. + + For an example set of masks that represent your mdev's current + configuration, simply cat ap_config. + + Setting an adapter or domain number greater than the maximum allowed for + the system will result in an error. + + This attribute is intended to be used by automation. End users would be + better served using the respective assign/unassign attributes for + adapters, domains, and control domains. * functions: @@ -550,7 +580,7 @@ These are the steps: following Kconfig elements selected: * IOMMU_SUPPORT * S390 - * ZCRYPT + * AP * VFIO * KVM @@ -969,6 +999,36 @@ the vfio_ap mediated device to which it is assigned as long as each new APQN resulting from plugging it in references a queue device bound to the vfio_ap device driver. +Driver Features +=============== +The vfio_ap driver exposes a sysfs file containing supported features. +This exists so third party tools (like Libvirt and mdevctl) can query the +availability of specific features. + +The features list can be found here: /sys/bus/matrix/devices/matrix/features + +Entries are space delimited. Each entry consists of a combination of +alphanumeric and underscore characters. + +Example: +cat /sys/bus/matrix/devices/matrix/features +guest_matrix dyn ap_config + +the following features are advertised: + +---------------+---------------------------------------------------------------+ +| Flag | Description | ++==============+===============================================================+ +| guest_matrix | guest_matrix attribute exists. It reports the matrix of | +| | adapters and domains that are or will be passed through to a | +| | guest when the mdev is attached to it. | ++--------------+---------------------------------------------------------------+ +| dyn | Indicates hot plug/unplug of AP adapters, domains and control | +| | domains for a guest to which the mdev is attached. | ++------------+-----------------------------------------------------------------+ +| ap_config | ap_config interface for one-shot modifications to mdev config | ++--------------+---------------------------------------------------------------+ + Limitations =========== Live guest migration is not supported for guests using AP devices without |