On 24.11.2025 13:33, Oleksii Kurochko wrote:
> @@ -28,6 +36,77 @@ unsigned char get_max_supported_mode(void)
> return max_gstage_mode.mode;
> }
>
> +static inline unsigned int calc_offset(const struct p2m_domain *p2m,
> + const unsigned int lvl,
> + const paddr_t gpa)
> +{
> + unsigned int off = (gpa >> P2M_GFN_LEVEL_SHIFT(lvl)) &
> + P2M_TABLE_OFFSET(p2m, lvl);
> +
> + /*
> + * For P2M_ROOT_LEVEL, `offset` ranges from 0 to 2047, since the root
> + * page table spans 4 consecutive 4KB pages.
> + * We want to return an index within one of these 4 pages.
> + * The specific page to use is determined by `p2m_get_root_pointer()`.
> + *
> + * Example: if `offset == 512`:
> + * - A single 4KB page holds 512 entries.
> + * - Therefore, entry 512 corresponds to index 0 of the second page.
> + *
> + * At all other levels, only one page is allocated, and `offset` is
> + * always in the range 0 to 511, since the VPN is 9 bits long.
> + */
> + return off & (PAGETABLE_ENTRIES - 1);
> +}
> +
> +#define P2M_MAX_ROOT_LEVEL 5
> +
> +#define P2M_BUILD_LEVEL_OFFSETS(p2m, var, addr) \
> + unsigned int var[P2M_MAX_ROOT_LEVEL] = {-1}; \
What use is this initializer? Slot 0 ...
> + BUG_ON(P2M_ROOT_LEVEL(p2m) >= P2M_MAX_ROOT_LEVEL); \
> + for ( unsigned int i = 0; i <= P2M_ROOT_LEVEL(p2m); i++ ) \
> + var[i] = calc_offset(p2m, i, addr);
... is guaranteed to be written to, afaics. With this simplified (or an
explanation given for why it is needed)
Acked-by: Jan Beulich <[email protected]>
Jan
