[PATCH v3 04/15] KVM: x86: Allocate memslot resources during prepare_memory_region()

[Sean Christopherson <sean.j.christopherson@intel.com>]

Allocate the various metadata structures associated with a memslot
during during kvm_arch_prepare_memory_region(), which paves the way for
removing kvm_arch_create_memslot() altogether.  Moving x86's memory
allocation only changes the order of kernel memory allocations between
x86 and common KVM code.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/x86.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 19a0dc96beca..fc63b1f07ba9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9628,6 +9628,12 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
 
 int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
 			    unsigned long npages)
+{
+	return 0;
+}
+
+static int kvm_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
+			      unsigned long npages)
 {
 	int i;
 
@@ -9705,6 +9711,9 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 				const struct kvm_userspace_memory_region *mem,
 				enum kvm_mr_change change)
 {
+	if (change == KVM_MR_CREATE)
+		return kvm_create_memslot(kvm, memslot,
+					  mem->memory_size >> PAGE_SHIFT);
 	return 0;
 }
 
-- 
2.22.0