KVM: Move x86's MMU memory cache helpers to common KVM code

Move x86's memory cache helpers to common KVM code so that they can be
reused by arm64 and MIPS in future patches.

Suggested-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200703023545.8771-16-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b528a59b0a84..2c2c0254c2d8 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -340,6 +340,61 @@ void kvm_reload_remote_mmus(struct kvm *kvm)
 	kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_RELOAD);
 }
 
+#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
+static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
+					       gfp_t gfp_flags)
+{
+	gfp_flags |= mc->gfp_zero;
+
+	if (mc->kmem_cache)
+		return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
+	else
+		return (void *)__get_free_page(gfp_flags);
+}
+
+int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
+{
+	void *obj;
+
+	if (mc->nobjs >= min)
+		return 0;
+	while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
+		obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
+		if (!obj)
+			return mc->nobjs >= min ? 0 : -ENOMEM;
+		mc->objects[mc->nobjs++] = obj;
+	}
+	return 0;
+}
+
+int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc)
+{
+	return mc->nobjs;
+}
+
+void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
+{
+	while (mc->nobjs) {
+		if (mc->kmem_cache)
+			kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]);
+		else
+			free_page((unsigned long)mc->objects[--mc->nobjs]);
+	}
+}
+
+void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
+{
+	void *p;
+
+	if (WARN_ON(!mc->nobjs))
+		p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
+	else
+		p = mc->objects[--mc->nobjs];
+	BUG_ON(!p);
+	return p;
+}
+#endif
+
 static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 {
 	mutex_init(&vcpu->mutex);