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Diffstat (limited to 'Documentation/virt/kvm/devices/vfio.rst')
| -rw-r--r-- | Documentation/virt/kvm/devices/vfio.rst | 47 |
1 files changed, 31 insertions, 16 deletions
diff --git a/Documentation/virt/kvm/devices/vfio.rst b/Documentation/virt/kvm/devices/vfio.rst index 08b544212638..c549143bb891 100644 --- a/Documentation/virt/kvm/devices/vfio.rst +++ b/Documentation/virt/kvm/devices/vfio.rst @@ -9,22 +9,34 @@ Device types supported: - KVM_DEV_TYPE_VFIO Only one VFIO instance may be created per VM. The created device -tracks VFIO groups in use by the VM and features of those groups -important to the correctness and acceleration of the VM. As groups -are enabled and disabled for use by the VM, KVM should be updated -about their presence. When registered with KVM, a reference to the -VFIO-group is held by KVM. +tracks VFIO files (group or device) in use by the VM and features +of those groups/devices important to the correctness and acceleration +of the VM. As groups/devices are enabled and disabled for use by the +VM, KVM should be updated about their presence. When registered with +KVM, a reference to the VFIO file is held by KVM. Groups: - KVM_DEV_VFIO_GROUP - -KVM_DEV_VFIO_GROUP attributes: - KVM_DEV_VFIO_GROUP_ADD: Add a VFIO group to VFIO-KVM device tracking - kvm_device_attr.addr points to an int32_t file descriptor - for the VFIO group. - KVM_DEV_VFIO_GROUP_DEL: Remove a VFIO group from VFIO-KVM device tracking - kvm_device_attr.addr points to an int32_t file descriptor - for the VFIO group. + KVM_DEV_VFIO_FILE + alias: KVM_DEV_VFIO_GROUP + +KVM_DEV_VFIO_FILE attributes: + KVM_DEV_VFIO_FILE_ADD: Add a VFIO file (group/device) to VFIO-KVM device + tracking + + kvm_device_attr.addr points to an int32_t file descriptor for the + VFIO file. + + KVM_DEV_VFIO_FILE_DEL: Remove a VFIO file (group/device) from VFIO-KVM + device tracking + + kvm_device_attr.addr points to an int32_t file descriptor for the + VFIO file. + +KVM_DEV_VFIO_GROUP (legacy kvm device group restricted to the handling of VFIO group fd): + KVM_DEV_VFIO_GROUP_ADD: same as KVM_DEV_VFIO_FILE_ADD for group fd only + + KVM_DEV_VFIO_GROUP_DEL: same as KVM_DEV_VFIO_FILE_DEL for group fd only + KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: attaches a guest visible TCE table allocated by sPAPR KVM. kvm_device_attr.addr points to a struct:: @@ -40,7 +52,10 @@ KVM_DEV_VFIO_GROUP attributes: - @tablefd is a file descriptor for a TCE table allocated via KVM_CREATE_SPAPR_TCE. -The GROUP_ADD operation above should be invoked prior to accessing the +The FILE/GROUP_ADD operation above should be invoked prior to accessing the device file descriptor via VFIO_GROUP_GET_DEVICE_FD in order to support drivers which require a kvm pointer to be set in their .open_device() -callback. +callback. It is the same for device file descriptor via character device +open which gets device access via VFIO_DEVICE_BIND_IOMMUFD. For such file +descriptors, FILE_ADD should be invoked before VFIO_DEVICE_BIND_IOMMUFD +to support the drivers mentioned in prior sentence as well. |