62 lines
2.0 KiB
ReStructuredText
62 lines
2.0 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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===================
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VFIO virtual device
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===================
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Device types supported:
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- KVM_DEV_TYPE_VFIO
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Only one VFIO instance may be created per VM. The created device
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tracks VFIO files (group or device) in use by the VM and features
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of those groups/devices important to the correctness and acceleration
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of the VM. As groups/devices are enabled and disabled for use by the
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VM, KVM should be updated about their presence. When registered with
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KVM, a reference to the VFIO file is held by KVM.
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Groups:
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KVM_DEV_VFIO_FILE
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alias: KVM_DEV_VFIO_GROUP
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KVM_DEV_VFIO_FILE attributes:
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KVM_DEV_VFIO_FILE_ADD: Add a VFIO file (group/device) to VFIO-KVM device
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tracking
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kvm_device_attr.addr points to an int32_t file descriptor for the
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VFIO file.
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KVM_DEV_VFIO_FILE_DEL: Remove a VFIO file (group/device) from VFIO-KVM
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device tracking
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kvm_device_attr.addr points to an int32_t file descriptor for the
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VFIO file.
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KVM_DEV_VFIO_GROUP (legacy kvm device group restricted to the handling of VFIO group fd):
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KVM_DEV_VFIO_GROUP_ADD: same as KVM_DEV_VFIO_FILE_ADD for group fd only
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KVM_DEV_VFIO_GROUP_DEL: same as KVM_DEV_VFIO_FILE_DEL for group fd only
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KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: attaches a guest visible TCE table
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allocated by sPAPR KVM.
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kvm_device_attr.addr points to a struct::
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struct kvm_vfio_spapr_tce {
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__s32 groupfd;
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__s32 tablefd;
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};
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where:
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- @groupfd is a file descriptor for a VFIO group;
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- @tablefd is a file descriptor for a TCE table allocated via
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KVM_CREATE_SPAPR_TCE.
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The FILE/GROUP_ADD operation above should be invoked prior to accessing the
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device file descriptor via VFIO_GROUP_GET_DEVICE_FD in order to support
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drivers which require a kvm pointer to be set in their .open_device()
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callback. It is the same for device file descriptor via character device
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open which gets device access via VFIO_DEVICE_BIND_IOMMUFD. For such file
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descriptors, FILE_ADD should be invoked before VFIO_DEVICE_BIND_IOMMUFD
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to support the drivers mentioned in prior sentence as well.
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