Re: [PATCH] x86/mm: fix __swp_entry_to_pte() for Xen PV guests

From: Juergen Gross
Date: Tue Apr 25 2023 - 04:40:57 EST


Ping?

On 06.03.23 13:32, Juergen Gross wrote:
Normally __swp_entry_to_pte() is never called with a value translating
to a valid PTE. The only known exception is pte_swap_tests(), resulting
in a WARN splat in Xen PV guests, as __pte_to_swp_entry() did
translate the PFN of the valid PTE to a guest local PFN, while
__swp_entry_to_pte() doesn't do the opposite translation.

Fix that by using __pte() in __swp_entry_to_pte() instead of open
coding the native variant of it.

For correctness do the similar conversion for __swp_entry_to_pmd().

Fixes: 05289402d717 ("mm/debug_vm_pgtable: add tests validating arch helpers for core MM features")
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
arch/x86/include/asm/pgtable_64.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
index 7929327abe00..a629b1b9f65a 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -237,8 +237,8 @@ static inline void native_pgd_clear(pgd_t *pgd)
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val((pte)) })
#define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val((pmd)) })
-#define __swp_entry_to_pte(x) ((pte_t) { .pte = (x).val })
-#define __swp_entry_to_pmd(x) ((pmd_t) { .pmd = (x).val })
+#define __swp_entry_to_pte(x) (__pte((x).val))
+#define __swp_entry_to_pmd(x) (__pmd((x).val))
extern void cleanup_highmap(void);

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