Re: [PATCH] mm: fix hugetlb page unmap count balance issue

[Andrew Morton]

On Fri, 12 May 2023 15:20:36 +0800 Junxiao Chang <junxiao.chang@xxxxxxxxx> wrote:

> hugetlb page usually is mapped with pmd, but occasionally it might be
> mapped with pte. QEMU can use udma-buf to create host dmabufs for guest
> framebuffers. When QEMU is launched with parameter "hugetlb=on",
> udmabuffer driver maps hugetlb page with pte in page fault handler.

Are there any other situations in which a hugetlb page is mapped in
this fashion?

If not, can QEMU be changed to map with a pmd?

So we get one less weird special case in MM.