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authorAlex Williamson <alex.williamson@redhat.com>2013-10-30 11:02:17 -0600
committerPaolo Bonzini <pbonzini@redhat.com>2013-10-30 19:02:03 +0100
commitec53500fae421e07c5d035918ca454a429732ef4 (patch)
tree3b9e0c67b9982f5b374e819a55cd510c14d481b8 /Documentation/virtual
parent84cffe499b9418d6c3b4de2ad9599cc2ec50c607 (diff)
kvm: Add VFIO device
So far we've succeeded at making KVM and VFIO mostly unaware of each other, but areas are cropping up where a connection beyond eventfds and irqfds needs to be made. This patch introduces a KVM-VFIO device that is meant to be a gateway for such interaction. The user creates the device and can add and remove VFIO groups to it via file descriptors. When a group is added, KVM verifies the group is valid and gets a reference to it via the VFIO external user interface. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/devices/vfio.txt22
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/devices/vfio.txt b/Documentation/virtual/kvm/devices/vfio.txt
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index 000000000000..ef51740c67ca
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+++ b/Documentation/virtual/kvm/devices/vfio.txt
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+VFIO virtual device
+===================
+
+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.
+
+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_DEV_VFIO_GROUP_DEL: Remove a VFIO group from VFIO-KVM device tracking
+
+For each, kvm_device_attr.addr points to an int32_t file descriptor
+for the VFIO group.