From 21828c99ee91bec94c3d2c32b3d5562ffdea980a Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 16 Apr 2018 16:57:15 +0530
Subject: [PATCH] powerpc/kvm: Switch kvm pmd allocator to custom allocator

References: bsc#1061840
Patch-mainline: v4.18-rc1
Git-commit: 21828c99ee91bec94c3d2c32b3d5562ffdea980a

In the next set of patches, we will switch pmd allocator to use page fragments
and the locking will be updated to split pmd ptlock. We want to avoid using
fragments for partition-scoped table. Use slab cache similar to level 4 table

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kvm/book3s_64_mmu_radix.c | 36 +++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index a57eafec4dc2..ccdf3761eec0 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -200,6 +200,7 @@ void kvmppc_radix_set_pte_at(struct kvm *kvm, unsigned long addr,
 }
 
 static struct kmem_cache *kvm_pte_cache;
+static struct kmem_cache *kvm_pmd_cache;
 
 static pte_t *kvmppc_pte_alloc(void)
 {
@@ -217,6 +218,16 @@ static inline int pmd_is_leaf(pmd_t pmd)
 	return !!(pmd_val(pmd) & _PAGE_PTE);
 }
 
+static pmd_t *kvmppc_pmd_alloc(void)
+{
+	return kmem_cache_alloc(kvm_pmd_cache, GFP_KERNEL);
+}
+
+static void kvmppc_pmd_free(pmd_t *pmdp)
+{
+	kmem_cache_free(kvm_pmd_cache, pmdp);
+}
+
 static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
 			     unsigned int level, unsigned long mmu_seq)
 {
@@ -239,7 +250,7 @@ static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
 	if (pud && pud_present(*pud) && !pud_huge(*pud))
 		pmd = pmd_offset(pud, gpa);
 	else if (level <= 1)
-		new_pmd = pmd_alloc_one(kvm->mm, gpa);
+		new_pmd = kvmppc_pmd_alloc();
 
 	if (level == 0 && !(pmd && pmd_present(*pmd) && !pmd_is_leaf(*pmd)))
 		new_ptep = kvmppc_pte_alloc();
@@ -382,7 +393,7 @@ static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
 	if (new_pud)
 		pud_free(kvm->mm, new_pud);
 	if (new_pmd)
-		pmd_free(kvm->mm, new_pmd);
+		kvmppc_pmd_free(new_pmd);
 	if (new_ptep)
 		kvmppc_pte_free(new_ptep);
 	return ret;
@@ -758,7 +769,7 @@ void kvmppc_free_radix(struct kvm *kvm)
 				kvmppc_pte_free(pte);
 				pmd_clear(pmd);
 			}
-			pmd_free(kvm->mm, pmd_offset(pud, 0));
+			kvmppc_pmd_free(pmd_offset(pud, 0));
 			pud_clear(pud);
 		}
 		pud_free(kvm->mm, pud_offset(pgd, 0));
@@ -770,20 +781,35 @@ void kvmppc_free_radix(struct kvm *kvm)
 
 static void pte_ctor(void *addr)
 {
-	memset(addr, 0, PTE_TABLE_SIZE);
+	memset(addr, 0, RADIX_PTE_TABLE_SIZE);
+}
+
+static void pmd_ctor(void *addr)
+{
+	memset(addr, 0, RADIX_PMD_TABLE_SIZE);
 }
 
 int kvmppc_radix_init(void)
 {
-	unsigned long size = sizeof(void *) << PTE_INDEX_SIZE;
+	unsigned long size = sizeof(void *) << RADIX_PTE_INDEX_SIZE;
 
 	kvm_pte_cache = kmem_cache_create("kvm-pte", size, size, 0, pte_ctor);
 	if (!kvm_pte_cache)
 		return -ENOMEM;
+
+	size = sizeof(void *) << RADIX_PMD_INDEX_SIZE;
+
+	kvm_pmd_cache = kmem_cache_create("kvm-pmd", size, size, 0, pmd_ctor);
+	if (!kvm_pmd_cache) {
+		kmem_cache_destroy(kvm_pte_cache);
+		return -ENOMEM;
+	}
+
 	return 0;
 }
 
 void kvmppc_radix_exit(void)
 {
 	kmem_cache_destroy(kvm_pte_cache);
+	kmem_cache_destroy(kvm_pmd_cache);
 }
-- 
2.13.7