Re: [PATCH v3 12/16] x86/virt/tdx: Add helpers to allow for pre-allocating pages

Kiryl Shutsemau
2025-09-19T09:55:40Z

On Thu, Sep 18, 2025 at 04:22:20PM -0700, Rick Edgecombe wrote:
> In the KVM fault path pagei, tables and private pages need to be

Typo.

> installed under a spin lock. This means that the operations around
> installing PAMT pages for them will not be able to allocate pages.
>

> +static inline struct page *get_tdx_prealloc_page(struct tdx_prealloc *prealloc)
> +{
> + struct page *page;
> +
> + page = list_first_entry_or_null(&prealloc->page_list, struct page, lru);
> + if (page) {
> + list_del(&page->lru);
> + prealloc->cnt--;
> + }
> +

For prealloc->cnt == 0, kvm_mmu_memory_cache_alloc() does allocation
with GFP_ATOMIC after WARN().

Do we want the same here?

--
Kiryl Shutsemau / Kirill A. Shutemov