On 22.05.2023 14:18, Oleksii Kurochko wrote: > --- a/xen/arch/riscv/include/asm/config.h > +++ b/xen/arch/riscv/include/asm/config.h > @@ -4,6 +4,42 @@ > #include <xen/const.h> > #include <xen/page-size.h> > > +/* > + * RISC-V64 Layout: > + * > + * #ifdef RV_STAGE1_MODE == SATP_MODE_SV39
Nit: #if please, not #ifdef. Also may I stress again that ideally this would be formatted such that when e.g. grep-ing for SATP_MODE_SV39, the matching line here would _not_ give the impression of being "a comment only" (making people possibly pay less attention)? My referral to the x86 way of doing things remains. > + * From the riscv-privileged doc: > + * When mapping between narrower and wider addresses, > + * RISC-V zero-extends a narrower physical address to a wider size. > + * The mapping between 64-bit virtual addresses and the 39-bit usable > + * address space of Sv39 is not based on zero-extension but instead > + * follows an entrenched convention that allows an OS to use one or > + * a few of the most-significant bits of a full-size (64-bit) virtual > + * address to quickly distinguish user and supervisor address regions. > + * > + * It means that: > + * top VA bits are simply ignored for the purpose of translating to PA. > + * > + * > ============================================================================ > + * Start addr | End addr | Size | Slot |area > description > + * > ============================================================================ > + * FFFFFFFFC0800000 | FFFFFFFFFFFFFFFF |1016 MB | L2 511 | Unused > + * FFFFFFFFC0600000 | FFFFFFFFC0800000 | 2 MB | L2 511 | Fixmap > + * FFFFFFFFC0200000 | FFFFFFFFC0600000 | 4 MB | L2 511 | FDT > + * FFFFFFFFC0000000 | FFFFFFFFC0200000 | 2 MB | L2 511 | Xen > + * ... | 1 GB | L2 510 | Unused > + * 0000003200000000 | 0000007f80000000 | 309 GB | L2 200-509 | Direct map And another, yet more minor nit: Would be nice if all addresses here were spelled uniformly, i.e. also with upper vs lower case of hex digit letter consistent. Jan > + * ... | 1 GB | L2 199 | Unused > + * 0000003100000000 | 00000031C0000000 | 3 GB | L2 196-198 | Frametable > + * ... | 1 GB | L2 195 | Unused > + * 0000003080000000 | 00000030C0000000 | 1 GB | L2 194 | VMAP > + * ... | 194 GB | L2 0 - 193 | Unused > + * > ============================================================================ > + * > + * #endif > + */ > + > #if defined(CONFIG_RISCV_64) > # define LONG_BYTEORDER 3 > # define ELFSIZE 64
