# \[PATCH 19/22\] x86/tboot: mark tboot\_mm as a kernel mm

- From: Kevin Brodsky \<hidden\>
- Date: 2026-07-14 14:07:38 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2026/07/17257835
- Thread: https://ratatoskr.run/linux-mm/2026/07/17257816/t.md

```text
tboot_mm is a kernel-owned address space used to build the
identity map for tboot shutdown. Mark it with MMF_KERNEL so
page table allocation and initialisation code treats its page tables
as kernel page tables.

Having marked tboot_mm as a kernel mm, we also need to convert
pte_alloc_map() (user PTE) to pte_alloc_kernel() (kernel PTE), and
drop the matching pte_unmap().

Assisted-by: Codex:GPT-5.5
Signed-off-by: Kevin Brodsky <redacted>
---
 arch/x86/kernel/tboot.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index 46b8f1f16676..08c899f88e41 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -99,6 +99,7 @@ static struct mm_struct tboot_mm = {
 	.pgd            = swapper_pg_dir,
 	.mm_users       = ATOMIC_INIT(2),
 	.mm_count       = ATOMIC_INIT(1),
+	.flags          = MM_FLAGS_INIT(MMF_KERNEL_MASK),
 	.write_protect_seq = SEQCNT_ZERO(tboot_mm.write_protect_seq),
 	MMAP_LOCK_INITIALIZER(init_mm)
 	.page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
@@ -129,11 +130,10 @@ static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
 	pmd = pmd_alloc(&tboot_mm, pud, vaddr);
 	if (!pmd)
 		return -1;
-	pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
+	pte = pte_alloc_kernel(pmd, vaddr);
 	if (!pte)
 		return -1;
 	set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
-	pte_unmap(pte);
 
 	/*
 	 * PTI poisons low addresses in the kernel page tables in the

-- 
2.51.2


```