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由 Jim Fehlig 提交于
'passthrough' is Xen-Specific guest configuration option new to Xen 4.13 that enables IOMMU mappings for a guest and hence whether it supports PCI passthrough. The default is disabled. See the xl.cfg(5) man page and xen.git commit babde47a3fe for more details. The default state of disabled prevents hotlugging PCI devices. However, if the guest configuration contains a PCI passthrough device at time of creation, libxl will automatically enable 'passthrough' and subsequent hotplugging of PCI devices will also be possible. It is not possible to unconditionally enable 'passthrough' since it would introduce a migration incompatibility due to guest ABI change. Instead, introduce another Xen hypervisor feature that can be used to enable guest PCI passthrough <features> <xen> <passthrough state='on'/> </xen> </features> To allow finer control over how IOMMU maps to guest P2M table, the passthrough element also supports a 'mode' attribute with values restricted to snyc_pt and share_pt, similar to xl.cfg(5) 'passthrough' setting . Signed-off-by: NJim Fehlig <jfehlig@suse.com> Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
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