On 20.07.2022 07:46, Penny Zheng wrote:
> When a static domain populates memory through populate_physmap at runtime,
> it shall retrieve reserved pages from resv_page_list to make sure that
> guest RAM is still restricted in statically configured memory regions.
> This commit also introduces a new helper acquire_reserved_page to make it
> work.
>
> Signed-off-by: Penny Zheng <penny.zh...@arm.com>
> ---
> v9 changes:
> - Use ASSERT_ALLOC_CONTEXT() in acquire_reserved_page
> - Add free_staticmem_pages to undo prepare_staticmem_pages when
> assign_domstatic_pages fails
May I suggest to re-consider naming of the various functions? Undoing
what "prepare" did by "free" is, well, counterintuitive.
> +/*
> + * Acquire a page from reserved page list(resv_page_list), when populating
> + * memory for static domain on runtime.
> + */
> +mfn_t acquire_reserved_page(struct domain *d, unsigned int memflags)
> +{
> + struct page_info *page;
> +
> + ASSERT_ALLOC_CONTEXT();
> +
> + /* Acquire a page from reserved page list(resv_page_list). */
> + spin_lock(&d->page_alloc_lock);
> + page = page_list_remove_head(&d->resv_page_list);
> + spin_unlock(&d->page_alloc_lock);
> + if ( unlikely(!page) )
> + return INVALID_MFN;
> +
> + if ( !prepare_staticmem_pages(page, 1, memflags) )
> + goto fail;
> +
> + if ( assign_domstatic_pages(d, page, 1, memflags) )
> + goto fail_assign;
> +
> + return page_to_mfn(page);
> +
> + fail_assign:
> + free_staticmem_pages(page, 1, memflags & MEMF_no_scrub);
> + fail:
> + page_list_add_tail(page, &d->resv_page_list);
> + return INVALID_MFN;
> +}
What about locking on this error path?
Jan
