On 12.02.2026 17:21, Oleksii Kurochko wrote: > Provide a RISC-V implementation of get_page_from_gfn(), matching the > semantics used by other architectures. > > For translated guests, this is implemented as a wrapper around > p2m_get_page_from_gfn(). For DOMID_XEN, which is not auto-translated, > provide a 1:1 RAM/MMIO mapping and perform the required validation and > reference counting. > > The function is implemented out-of-line rather than as a static inline, > to avoid header ordering issues where struct domain is incomplete when > asm/p2m.h is included, leading to build failures: > In file included from ./arch/riscv/include/asm/domain.h:10, > from ./include/xen/domain.h:16, > from ./include/xen/sched.h:11, > from ./include/xen/event.h:12, > from common/cpu.c:3: > ./arch/riscv/include/asm/p2m.h: In function 'get_page_from_gfn': > ./arch/riscv/include/asm/p2m.h:50:33: error: invalid use of undefined type > 'struct domain' > 50 | #define p2m_get_hostp2m(d) (&(d)->arch.p2m) > | ^~ > ./arch/riscv/include/asm/p2m.h:180:38: note: in expansion of macro > 'p2m_get_hostp2m' > 180 | return p2m_get_page_from_gfn(p2m_get_hostp2m(d), _gfn(gfn), > t); > | ^~~~~~~~~~~~~~~ > make[2]: *** [Rules.mk:253: common/cpu.o] Error 1 > make[1]: *** [build.mk:72: common] Error 2 > make: *** [Makefile:623: xen] Error 2
Surely this can be addressed, when x86 and Arm have the function as inline? > Signed-off-by: Oleksii Kurochko <[email protected]> > --- > Does it make sense to make this function almost fully generic? > > It looks like most of the logic here is architecture-independent and identical > across architectures, except for the following points: > > 1. ``` > if ( likely(d != dom_xen) ) > ``` > > This could be made generic by introducing paging_mode_translate() for ARM > and defining it as `(d != dom_xen)` there. > > 2. ``` > if ( t ) > *t = likely(d != dom_io) ? p2m_ram_rw : p2m_mmio_direct_io; > ``` > > Here, only `p2m_mmio_direct_io` appears to be architecture-specific. This > could be abstracted via a helper such as `dom_io_p2m_type()` and used here > instead. With P2M stuff I'd be careful. Abstracting the two aspects above may make future arch-specific changes there more difficult. > --- a/xen/arch/riscv/p2m.c > +++ b/xen/arch/riscv/p2m.c > @@ -1557,3 +1557,31 @@ void p2m_handle_vmenter(void) > flush_tlb_guest_local(); > } > } > + > +struct page_info *get_page_from_gfn(struct domain *d, unsigned long gfn, > + p2m_type_t *t, p2m_query_t q) > +{ > + struct page_info *page; > + > + /* > + * Special case for DOMID_XEN as it is the only domain so far that is > + * not auto-translated. > + */ Once again something taken verbatim from Arm. Yes, dom_xen can in fact appear here, but it's not a real domain, has no memory truly assigned to it, has no GFN space, and hence calling it translated (or not) is simply wrong (at best: misleading). IOW ... > + if ( likely(d != dom_xen) ) > + return p2m_get_page_from_gfn(p2m_get_hostp2m(d), _gfn(gfn), t); > + > + /* Non-translated guests see 1-1 RAM / MMIO mappings everywhere */ ... this comment would also want re-wording. > + if ( t ) > + *t = p2m_invalid; > + > + page = mfn_to_page(_mfn(gfn)); > + > + if ( !mfn_valid(_mfn(gfn)) || !get_page(page, d) ) > + return NULL; > + > + if ( t ) > + *t = likely(d != dom_io) ? p2m_ram_rw : p2m_mmio_direct_io; If only dom_xen can make it here, why the check for dom_io? Jan
