x86/mm: Make set_pmd_at() paravirt aware

jgross1 · KAGA-KOKO · commit 20e55bc17dd0 · 2019-02-10T08:47:12.000+01:00
set_pmd_at() calls native_set_pmd() unconditionally on x86. This was fine as long as only huge page entries were written via set_pmd_at(), as Xen pv guests don't support those. Commit 2c91bd4 ("mm: speed up mremap by 20x on large regions") introduced a usage of set_pmd_at() possible on pv guests, leading to failures like: BUG: unable to handle kernel paging request at ffff888023e26778 #PF error: [PROT] [WRITE] RIP: e030:move_page_tables+0x7c1/0xae0 move_vma.isra.3+0xd1/0x2d0 __se_sys_mremap+0x3c6/0x5b0 do_syscall_64+0x49/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Make set_pmd_at() paravirt aware by just letting it use set_pmd(). Fixes: 2c91bd4 ("mm: speed up mremap by 20x on large regions") Reported-by: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: xen-devel@lists.xenproject.org Cc: boris.ostrovsky@oracle.com Cc: sstabellini@kernel.org Cc: hpa@zytor.com Cc: bp@alien8.de Cc: torvalds@linux-foundation.org Link: https://lkml.kernel.org/r/20190210074056.11842-1-jgross@suse.com
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
@@ -1065,7 +1065,7 @@ static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
 static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 			      pmd_t *pmdp, pmd_t pmd)
 {
-	native_set_pmd(pmdp, pmd);
+	set_pmd(pmdp, pmd);
 }
 
 static inline void set_pud_at(struct mm_struct *mm, unsigned long addr,

Original file line number	Diff line number	Diff line change
`@@ -1065,7 +1065,7 @@ static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,`
`1065`	`1065`	`static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,`
`1066`	`1066`	`pmd_t *pmdp, pmd_t pmd)`
`1067`	`1067`	`{`
`1068`		`- native_set_pmd(pmdp, pmd);`
	`1068`	`+ set_pmd(pmdp, pmd);`
`1069`	`1069`	`}`
`1070`	`1070`
`1071`	`1071`	`static inline void set_pud_at(struct mm_struct *mm, unsigned long addr,`