linux-kernel - [RFC PATCH 01/18] x86/mm/encrypt: add the missing pte

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Message-Id: <20220429133552.33768-2-zhengqi.arch@bytedance.com>
Date:   Fri, 29 Apr 2022 21:35:35 +0800
From:   Qi Zheng <zhengqi.arch@...edance.com>
To:     akpm@...ux-foundation.org, tglx@...utronix.de,
        kirill.shutemov@...ux.intel.com, mika.penttila@...tfour.com,
        david@...hat.com, jgg@...dia.com, tj@...nel.org, dennis@...nel.org,
        ming.lei@...hat.com
Cc:     linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, songmuchun@...edance.com,
        zhouchengming@...edance.com, Qi Zheng <zhengqi.arch@...edance.com>
Subject: [RFC PATCH 01/18] x86/mm/encrypt: add the missing pte_unmap() call

The paired pte_unmap() call is missing before the sme_populate_pgd()
returns. Although this code only runs under the CONFIG_X86_64, for
the correctness of the code semantics, it is necessary to add a
paired pte_unmap() call.

Signed-off-by: Qi Zheng <zhengqi.arch@...edance.com>
---
 arch/x86/mm/mem_encrypt_identity.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index b43bc24d2bb6..6d323230320a 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -190,6 +190,7 @@ static void __init sme_populate_pgd(struct sme_populate_pgd_data *ppd)
 	pte = pte_offset_map(pmd, ppd->vaddr);
 	if (pte_none(*pte))
 		set_pte(pte, __pte(ppd->paddr | ppd->pte_flags));
+	pte_unmap(pte);
 }
 
 static void __init __sme_map_range_pmd(struct sme_populate_pgd_data *ppd)
-- 
2.20.1