x86/paravirt: Remove set_pte_at() pv-op

On x86 set_pte_at() is now always falling back to set_pte(). So instead
of having this fallback after the paravirt maze just drop the
set_pte_at paravirt operation and let set_pte_at() use the set_pte()
function directly.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200815100641.26362-6-jgross@suse.com

arch/x86/include/asm/paravirt.h

@@ -412,12 +412,6 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
 	PVOP_VCALL2(mmu.set_pte, ptep, pte.pte);
 }
 
-static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
-			      pte_t *ptep, pte_t pte)
-{
-	PVOP_VCALL4(mmu.set_pte_at, mm, addr, ptep, pte.pte);
-}
-
 static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
 {
 	PVOP_VCALL2(mmu.set_pmd, pmdp, native_pmd_val(pmd));
@@ -510,7 +504,7 @@ static inline void set_pte_atomic(pte_t *ptep, pte_t pte)
 static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
 			     pte_t *ptep)
 {
-	set_pte_at(mm, addr, ptep, __pte(0));
+	set_pte(ptep, __pte(0));
 }
 
 static inline void pmd_clear(pmd_t *pmdp)

arch/x86/include/asm/paravirt_types.h

@@ -242,8 +242,6 @@ struct pv_mmu_ops {
 
 	/* Pagetable manipulation functions */
 	void (*set_pte)(pte_t *ptep, pte_t pteval);
-	void (*set_pte_at)(struct mm_struct *mm, unsigned long addr,
-			   pte_t *ptep, pte_t pteval);
 	void (*set_pmd)(pmd_t *pmdp, pmd_t pmdval);
 
 	pte_t (*ptep_modify_prot_start)(struct vm_area_struct *vma, unsigned long addr,

arch/x86/include/asm/pgtable.h

@@ -63,7 +63,6 @@ extern pmdval_t early_pmd_flags;
 #include <asm/paravirt.h>
 #else  /* !CONFIG_PARAVIRT_XXL */
 #define set_pte(ptep, pte)		native_set_pte(ptep, pte)
-#define set_pte_at(mm, addr, ptep, pte)	native_set_pte_at(mm, addr, ptep, pte)
 
 #define set_pte_atomic(ptep, pte)					\
 	native_set_pte_atomic(ptep, pte)
@@ -1033,10 +1032,10 @@ static inline pud_t native_local_pudp_get_and_clear(pud_t *pudp)
 	return res;
 }
 
-static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
-				     pte_t *ptep , pte_t pte)
+static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
+			      pte_t *ptep, pte_t pte)
 {
-	native_set_pte(ptep, pte);
+	set_pte(ptep, pte);
 }
 
 static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,

arch/x86/kernel/paravirt.c

@@ -360,7 +360,6 @@ struct paravirt_patch_template pv_ops = {
 	.mmu.release_p4d	= paravirt_nop,
 
 	.mmu.set_pte		= native_set_pte,
-	.mmu.set_pte_at		= native_set_pte_at,
 	.mmu.set_pmd		= native_set_pmd,
 
 	.mmu.ptep_modify_prot_start	= __ptep_modify_prot_start,

arch/x86/xen/mmu_pv.c

@@ -285,13 +285,6 @@ static void xen_set_pte(pte_t *ptep, pte_t pteval)
 	__xen_set_pte(ptep, pteval);
 }
 
-static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
-		    pte_t *ptep, pte_t pteval)
-{
-	trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
-	__xen_set_pte(ptep, pteval);
-}
-
 pte_t xen_ptep_modify_prot_start(struct vm_area_struct *vma,
 				 unsigned long addr, pte_t *ptep)
 {
@@ -2105,7 +2098,6 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
 	.release_pmd = xen_release_pmd_init,
 
 	.set_pte = xen_set_pte_init,
-	.set_pte_at = xen_set_pte_at,
 	.set_pmd = xen_set_pmd_hyper,
 
 	.ptep_modify_prot_start = __ptep_modify_prot_start,

include/trace/events/xen.h

@@ -153,26 +153,6 @@ DECLARE_EVENT_CLASS(xen_mmu__set_pte,
 
 DEFINE_XEN_MMU_SET_PTE(xen_mmu_set_pte);
 
-TRACE_EVENT(xen_mmu_set_pte_at,
-	    TP_PROTO(struct mm_struct *mm, unsigned long addr,
-		     pte_t *ptep, pte_t pteval),
-	    TP_ARGS(mm, addr, ptep, pteval),
-	    TP_STRUCT__entry(
-		    __field(struct mm_struct *, mm)
-		    __field(unsigned long, addr)
-		    __field(pte_t *, ptep)
-		    __field(pteval_t, pteval)
-		    ),
-	    TP_fast_assign(__entry->mm = mm;
-			   __entry->addr = addr;
-			   __entry->ptep = ptep;
-			   __entry->pteval = pteval.pte),
-	    TP_printk("mm %p addr %lx ptep %p pteval %0*llx (raw %0*llx)",
-		      __entry->mm, __entry->addr, __entry->ptep,
-		      (int)sizeof(pteval_t) * 2, (unsigned long long)pte_val(native_make_pte(__entry->pteval)),
-		      (int)sizeof(pteval_t) * 2, (unsigned long long)__entry->pteval)
-	);
-
 TRACE_DEFINE_SIZEOF(pmdval_t);
 
 TRACE_EVENT(xen_mmu_set_pmd,