For post launch VM, ACRN supports PTM under these conditions:
1. HW implements a simple PTM hierarchy: PTM requestor device (ep) is
directly connected to PTM root capable root port. Or
2. ptm requestor itself is root complex integrated ep.
Currently acrn doesn't support emulation of other type of PTM hiearchy, such
as if there is an intermediate PTM node (for example, switch) inbetween
PTM requestor and PTM root.
To avoid VM touching physical hardware, acrn hv ensures PTM is always enabled
in the hardware.
During hv's pci init, if root port is ptm capable,
hv will enable PTM on that root port. In addition,
log error (and don't enable PTM) if ptm root
capability is on intermediate node other than root port.
V2:
- Modify commit messages to clarify the limitation
of current PTM implementation.
- Fix code that may fail FUSA
- Remove pci_ptm_info() and put info log inside pci_enable_ptm_root().
Tracked-On: #5915
Signed-off-by: Rong Liu <rong.l.liu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
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