[PATCH 09/60] kvm: Introduce struct kvm_plane

[Jörg Rödel]

From: Paolo Bonzini <pbonzini@xxxxxxxxxx>

Introduce a data structure to keep VM-wide per-plane state. Initialize
the structure with a back-pointer to struct kvm and the plane level
the structure represents.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Co-developed-by: Joerg Roedel <joerg.roedel@xxxxxxx>
Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 include/linux/kvm_host.h |  7 +++++++
 include/uapi/linux/kvm.h |  6 ++++++
 virt/kvm/kvm_main.c      | 41 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4c14aee1fb06..5be4c9f118b4 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -767,6 +767,11 @@ struct kvm_memslots {
 	int node_idx;
 };
 
+struct kvm_plane {
+	struct kvm *kvm;
+	unsigned level;
+};
+
 struct kvm {
 #ifdef KVM_HAVE_MMU_RWLOCK
 	rwlock_t mmu_lock;
@@ -806,6 +811,8 @@ struct kvm {
 	spinlock_t gpc_lock;
 	struct list_head gpc_list;
 
+	struct kvm_plane *planes[KVM_MAX_PLANES];
+
 	/*
 	 * created_vcpus is protected by kvm->lock, and is incremented
 	 * at the beginning of KVM_CREATE_VCPU.  online_vcpus is only
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 6c8afa2047bf..813f964a6dc1 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -730,6 +730,11 @@ struct kvm_enable_cap {
 #define KVM_GET_EMULATED_CPUID	  _IOWR(KVMIO, 0x09, struct kvm_cpuid2)
 #define KVM_GET_MSR_FEATURE_INDEX_LIST    _IOWR(KVMIO, 0x0a, struct kvm_msr_list)
 
+/*
+ * Maximum number of supported planes
+ */
+#define KVM_MAX_PLANES	16
+
 /*
  * Extension capability list.
  */
@@ -996,6 +1001,7 @@ struct kvm_enable_cap {
 #define KVM_CAP_S390_USER_OPEREXEC 246
 #define KVM_CAP_S390_KEYOP 247
 #define KVM_CAP_S390_VSIE_ESAMODE 248
+#define KVM_CAP_PLANES 249
 
 struct kvm_irq_routing_irqchip {
 	__u32 irqchip;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 881f92d7a469..a68469c6d12e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1095,6 +1095,38 @@ static inline struct kvm_io_bus *kvm_get_bus_for_destruction(struct kvm *kvm,
 static int kvm_enable_virtualization(void);
 static void kvm_disable_virtualization(void);
 
+static struct kvm_plane *kvm_create_plane(struct kvm *kvm, unsigned plane_level)
+{
+	struct kvm_plane *plane = kzalloc(sizeof(*plane), GFP_KERNEL_ACCOUNT);
+
+	if (!plane)
+		return NULL;
+
+	plane->kvm = kvm;
+	plane->level = plane_level;
+
+	kvm->planes[plane_level] = plane;
+
+	return plane;
+}
+
+static void kvm_destroy_one_plane(struct kvm_plane *plane)
+{
+	kfree(plane);
+}
+
+static void kvm_destroy_planes(struct kvm *kvm)
+{
+	int i;
+
+	for (i = 0; i < KVM_MAX_PLANES; ++i) {
+		if (kvm->planes[i] == NULL)
+			continue;
+		kvm_destroy_one_plane(kvm->planes[i]);
+		kvm->planes[i] = NULL;
+	}
+}
+
 static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
 {
 	struct kvm *kvm = kvm_arch_alloc_vm();
@@ -1127,6 +1159,12 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
 
 	BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
 
+	/* Initialize planes array and allocate plane 0 */
+	if (kvm_create_plane(kvm, 0) == NULL) {
+		r = -ENOMEM;
+		goto out_no_planes;
+	}
+
 	/*
 	 * Force subsequent debugfs file creations to fail if the VM directory
 	 * is not created (by kvm_create_vm_debugfs()).
@@ -1225,6 +1263,8 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
 out_err_no_irq_srcu:
 	cleanup_srcu_struct(&kvm->srcu);
 out_err_no_srcu:
+	kvm_destroy_planes(kvm);
+out_no_planes:
 	kvm_arch_free_vm(kvm);
 	mmdrop(current->mm);
 	return ERR_PTR(r);
@@ -1304,6 +1344,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
 	xa_destroy(&kvm->mem_attr_array);
 #endif
 	kvm_arch_free_vm(kvm);
+	kvm_destroy_planes(kvm);
 	preempt_notifier_dec();
 	kvm_disable_virtualization();
 	mmdrop(mm);
-- 
2.53.0