linux-kernel - [PATCH] x86/mm/cpa: set PAGE_KERNEL in __set_pages

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Message-Id: <20220506051940.156952-1-42.hyeyoo@gmail.com>
Date:   Fri,  6 May 2022 14:19:39 +0900
From:   Hyeonggon Yoo <42.hyeyoo@...il.com>
To:     Rick Edgecombe <rick.p.edgecombe@...el.com>
Cc:     42.hyeyoo@...il.com, Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Brijesh Singh <brijesh.singh@....com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Tianyu Lan <Tianyu.Lan@...rosoft.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] x86/mm/cpa: set PAGE_KERNEL in __set_pages_p()

__set_pages_np() not only clears _PAGE_PRESENT and _PAGE_RW, but also
clears _PAGE_GLOBAL to avoid confusing _PAGE_GLOBAL as _PAGE_PROTNONE
when the PTE is not present.

Common usage for __set_pages_p() is to call it after __set_pages_np().
Therefore calling __set_pages_p() after __set_pages_np() clears
_PAGE_GLOBAL, making it unable to globally shared in TLB.

As they are called by set_direct_map_{invalid,default}_noflush(),
pages in direct map cannot be globally shared in TLB after being used by
vmalloc, secretmem, and hibernation.

So set PAGE_KERNEL isntead of __pgprot(_PAGE_PRESENT | _PAGE_RW) in
__set_pages_p().

Signed-off-by: Hyeonggon Yoo <42.hyeyoo@...il.com>
---
 arch/x86/mm/pat/set_memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index abf5ed76e4b7..fcb6147c4cd4 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2177,7 +2177,7 @@ static int __set_pages_p(struct page *page, int numpages)
 	struct cpa_data cpa = { .vaddr = &tempaddr,
 				.pgd = NULL,
 				.numpages = numpages,
-				.mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW),
+				.mask_set = PAGE_KERNEL,
 				.mask_clr = __pgprot(0),
 				.flags = 0};
 
-- 
2.32.0