On 22.12.2025 17:37, Oleksii Kurochko wrote:
> @@ -370,24 +396,96 @@ static struct page_info *p2m_alloc_page(struct
> p2m_domain *p2m)
> return pg;
> }
>
> -static int p2m_set_type(pte_t *pte, p2m_type_t t)
> +/*
> + * `pte` – PTE entry for which the type `t` will be stored.
> + *
> + * If `t` >= p2m_first_external, a valid `ctx` must be provided.
> + */
> +static void p2m_set_type(pte_t *pte, p2m_type_t t,
> + const struct p2m_pte_ctx *ctx)
> {
> - int rc = 0;
> + struct page_info **md_pg;
> + struct md_t *metadata = NULL;
>
> - if ( t > p2m_first_external )
> - panic("unimplemeted\n");
> - else
> - pte->pte |= MASK_INSR(t, P2M_TYPE_PTE_BITS_MASK);
> + /*
> + * It is sufficient to compare ctx->index with PAGETABLE_ENTRIES because,
> + * even for the p2m root page table (which is a 16 KB page allocated as
> + * four 4 KB pages), calc_offset() guarantees that the page-table index
> + * will always fall within the range [0, 511].
> + */
> + ASSERT(ctx && ctx->index < PAGETABLE_ENTRIES);
>
> - return rc;
> + /*
> + * At the moment, p2m_get_root_pointer() returns one of four possible p2m
> + * root pages, so there is no need to search for the correct ->pt_page
> + * here.
> + * Non-root page tables are 4 KB pages, so simply using ->pt_page is
> + * sufficient.
> + */
> + md_pg = &ctx->pt_page->v.md.pg;
> +
> + if ( !*md_pg && (t >= p2m_first_external) )
> + {
> + /*
> + * Since p2m_alloc_page() initializes an allocated page with
> + * zeros, p2m_invalid is expected to have the value 0 as well.
> + */
> + BUILD_BUG_ON(p2m_invalid);
> +
> + ASSERT(ctx->p2m);
I think I previously asked for this to be moved out of the if(). Else you
may not notice a caller side issue until a point where a metadata page
actually needs allocating. (This could simply be folded into the earlier
ASSERT().)
Jan
