Hi Luca, On 26/09/2023 11:52, Luca Fancellu wrote: > > >> On 26 Sep 2023, at 06:33, Leo Yan <[email protected]> wrote: >> >> During the Linux kernel booting, an error is reported by the Xen >> hypervisor: >> >> (XEN) arch/arm/p2m.c:2202: d0v0: Failing to acquire the MFN 0x1a02dc >> >> The kernel attempts to use an invalid memory frame number, which can be >> converted to: 0x1a02dc << PAGE_SHIFT, resulting in 0x1_a02d_c000. >> >> The invalid memory frame falls into a reserved memory node, which is >> defined in the device tree as below: >> >> reserved-memory { >> #address-cells = <0x02>; >> #size-cells = <0x02>; >> ranges; >> >> ... >> >> ethosn_reserved { >> compatible = "shared-dma-pool"; >> reg = <0x01 0xa0000000 0x00 0x20000000>; >> status = "disabled"; >> no-map; >> }; >> >> ... >> }; >> >> Xen excludes all reserved memory regions from the frame management >> through the dt_unreserved_regions() function. On the other hand, the >> reserved memory nodes are passed to the Linux kernel. However, the Linux >> kernel ignores the 'ethosn_reserved' node since its status is >> "disabled". This leads to the Linux kernel to allocate pages from the >> reserved memory range. > > I might be wrong, but reading the specifications seems that “status” is not a > property > of the child nodes of /reserved-memory, so I’m not sure Xen should do > something about it. Please take a look at dt documentation (v0.4) for /memory and /reserved-memory. Under the tables listing possible properties, there is a statement: Note: All other standard properties (Section 2.3) are allowed but are optional.
"status" is part of standard properties so it is perfectly fine for /memory or /reserved-memory nodes to have it defined. ~Michal
