Re: [PATCH v7 05/19] xen/riscv: add root page table allocation

[Oleksii Kurochko]

On 12/18/25 2:58 PM, Jan Beulich wrote:

On 16.12.2025 17:55, Oleksii Kurochko wrote:

@@ -30,6 +34,11 @@ struct p2m_domain {
      /* Pages used to construct the p2m */
      struct page_list_head pages;

+ /* The root of the p2m tree. May be concatenated */

+    struct page_info *root;
+
+    struct gstage_mode_desc mode;

Why would this need a copy (instance) of the struct? Can't this be a
(const) pointer into the static array that currently is local to
gstage_mode_detect()? Similarly there max_gstage_mode could be a pointer
rather than a separate instance of the struct.

Good point. I will take that into account when will deal with TODO.

Thanks.

~ Oleksii

Yes, there is a connection to ...

@@ -124,6 +193,24 @@ int p2m_init(struct domain *d)
      rwlock_init(&p2m->lock);
      INIT_PAGE_LIST_HEAD(&p2m->pages);

+ /*

+     * Currently, the infrastructure required to enable CONFIG_HAS_PASSTHROUGH
+     * is not ready for RISC-V support.
+     *
+     * When CONFIG_HAS_PASSTHROUGH=y, p2m->clean_dcache must be properly
+     * initialized.
+     * At the moment, it defaults to false because the p2m structure is
+     * zero-initialized.
+     */
+#ifdef CONFIG_HAS_PASSTHROUGH
+#   error "Add init of p2m->clean_dcache"
+#endif
+
+    /* TODO: don't hardcode used for a domain g-stage mode. */
+    p2m->mode.mode = HGATP_MODE_SV39X4;
+    p2m->mode.paging_levels = 2;
+    safe_strcpy(p2m->mode.name, "Sv39x4");

... this TODO, but surely this code could similarly be made reference the
(then) global array.