From a9e00d8349c98e0973c8b0d671d69e838f7b5bcc Mon Sep 17 00:00:00 2001 From: Janosch Frank Date: Fri, 13 Jul 2018 11:28:37 +0100 Subject: [PATCH] s390/mm: Add huge page gmap linking support Let's allow huge pmd linking when enabled through the KVM_CAP_S390_HPAGE_1M capability. Also we can now restrict gmap invalidation and notification to the cases where the capability has been activated and save some cycles when that's not the case. Signed-off-by: Janosch Frank Reviewed-by: David Hildenbrand --- arch/s390/include/asm/mmu.h | 2 ++ arch/s390/include/asm/mmu_context.h | 1 + arch/s390/mm/gmap.c | 9 ++++++--- arch/s390/mm/pgtable.c | 8 ++++---- 4 files changed, 13 insertions(+), 7 deletions(-) diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h index f5ff9dbad8ac..f31a15044c24 100644 --- a/arch/s390/include/asm/mmu.h +++ b/arch/s390/include/asm/mmu.h @@ -24,6 +24,8 @@ typedef struct { unsigned int uses_skeys:1; /* The mmu context uses CMM. */ unsigned int uses_cmm:1; + /* The gmaps associated with this context are allowed to use huge pages. */ + unsigned int allow_gmap_hpage_1m:1; } mm_context_t; #define INIT_MM_CONTEXT(name) \ diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h index d16bc79c30bb..0717ee76885d 100644 --- a/arch/s390/include/asm/mmu_context.h +++ b/arch/s390/include/asm/mmu_context.h @@ -32,6 +32,7 @@ static inline int init_new_context(struct task_struct *tsk, mm->context.has_pgste = 0; mm->context.uses_skeys = 0; mm->context.uses_cmm = 0; + mm->context.allow_gmap_hpage_1m = 0; #endif switch (mm->context.asce_limit) { case _REGION2_SIZE: diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 736ed32a83c5..bb44990c8212 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2,8 +2,10 @@ /* * KVM guest address space mapping code * - * Copyright IBM Corp. 2007, 2016 + * Copyright IBM Corp. 2007, 2016, 2018 * Author(s): Martin Schwidefsky + * David Hildenbrand + * Janosch Frank */ #include @@ -588,8 +590,8 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr) return -EFAULT; pmd = pmd_offset(pud, vmaddr); VM_BUG_ON(pmd_none(*pmd)); - /* large pmds cannot yet be handled */ - if (pmd_large(*pmd)) + /* Are we allowed to use huge pages? */ + if (pmd_large(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m) return -EFAULT; /* Link gmap segment table entry location to page table. */ rc = radix_tree_preload(GFP_KERNEL); @@ -1632,6 +1634,7 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, unsigned long limit; int rc; + BUG_ON(parent->mm->context.allow_gmap_hpage_1m); BUG_ON(gmap_is_shadow(parent)); spin_lock(&parent->shadow_lock); sg = gmap_find_shadow(parent, asce, edat_level); diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 37d68706f5aa..f2cc7da473e4 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -347,7 +347,7 @@ static inline void pmdp_idte_local(struct mm_struct *mm, mm->context.asce, IDTE_LOCAL); else __pmdp_idte(addr, pmdp, 0, 0, IDTE_LOCAL); - if (mm_has_pgste(mm)) + if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m) gmap_pmdp_idte_local(mm, addr); } @@ -357,15 +357,15 @@ static inline void pmdp_idte_global(struct mm_struct *mm, if (MACHINE_HAS_TLB_GUEST) { __pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE, mm->context.asce, IDTE_GLOBAL); - if (mm_has_pgste(mm)) + if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m) gmap_pmdp_idte_global(mm, addr); } else if (MACHINE_HAS_IDTE) { __pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL); - if (mm_has_pgste(mm)) + if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m) gmap_pmdp_idte_global(mm, addr); } else { __pmdp_csp(pmdp); - if (mm_has_pgste(mm)) + if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m) gmap_pmdp_csp(mm, addr); } } -- 2.30.2