[PATCH 4/6] KVM: MMU: introduce mmu_topup_memory_cache_atomic()

[Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>]

Introduce mmu_topup_memory_cache_atomic(), it support topup memory
cache in atomic context.

And, when we prefetch pte, we need topup the rmap's cache

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 arch/x86/kvm/mmu.c |   29 +++++++++++++++++++++++++----
 1 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 734b106..92ff099 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -290,15 +290,16 @@ static void __set_spte(u64 *sptep, u64 spte)
 #endif
 }
 
-static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
-				  struct kmem_cache *base_cache, int min)
+static int __mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
+				    struct kmem_cache *base_cache, int min,
+				    int max, gfp_t flags)
 {
 	void *obj;
 
 	if (cache->nobjs >= min)
 		return 0;
-	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
-		obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
+	while (cache->nobjs < max) {
+		obj = kmem_cache_zalloc(base_cache, flags);
 		if (!obj)
 			return -ENOMEM;
 		cache->objects[cache->nobjs++] = obj;
@@ -306,6 +307,26 @@ static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
 	return 0;
 }
 
+static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
+				  struct kmem_cache *base_cache, int min)
+{
+	return __mmu_topup_memory_cache(cache, base_cache, min,
+				ARRAY_SIZE(cache->objects), GFP_KERNEL);
+}
+
+static int mmu_topup_memory_cache_atomic(struct kvm_mmu_memory_cache *cache,
+				  struct kmem_cache *base_cache, int min)
+{
+	return __mmu_topup_memory_cache(cache, base_cache, min, min,
+					GFP_ATOMIC);
+}
+
+static int pte_prefetch_topup_memory_cache(struct kvm_vcpu *vcpu)
+{
+	return mmu_topup_memory_cache_atomic(&vcpu->arch.mmu_rmap_desc_cache,
+					     rmap_desc_cache, 1);
+}
+
 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
 				  struct kmem_cache *cache)
 {
-- 
1.6.1.2