RE: [PATCH v2 02/12] cxl/core: Check physical address before mapping it in devm_cxl_iomap_block()

[Dan Williams]

Robert Richter wrote:
> The physical base address of a CXL range can be invalid and is then
> set to CXL_RESOURCE_NONE. In general software shall prevent such
> situations, but it is hard to proof this may never happen. E.g. in
> add_port_attach_ep() there this the following:
> 
>       component_reg_phys = find_component_registers(uport_dev);
>       port = devm_cxl_add_port(&parent_port->dev, uport_dev,
>               component_reg_phys, parent_dport);
> 
> find_component_registers() and subsequent functions (e.g.
> cxl_regmap_to_base()) may return CXL_RESOURCE_NONE. But it is written
> to port without any further check in cxl_port_alloc():
> 
>       port->component_reg_phys = component_reg_phys;
> 
> It is then later directly used in devm_cxl_setup_hdm() to map io
> ranges with devm_cxl_iomap_block(). Just an example...
> 
> Check this condition. Also do not fail silently like an ioremap()
> failure, use a WARN_ON_ONCE() for it.
> 
> Signed-off-by: Robert Richter <rrichter@xxxxxxx>

Looks good to me, applied for v6.2