KVM: x86: Allocate memslot resources during prepare_memory_region()

Allocate the various metadata structures associated with a new memslot
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.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6387917..94ea7b9 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9876,6 +9876,12 @@ 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_alloc_memslot_metadata(struct kvm_memory_slot *slot,
+                                     unsigned long npages)
+{
        int i;
 
        /*
@@ -9966,10 +9972,9 @@ 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_MOVE)
-               return kvm_arch_create_memslot(kvm, memslot,
-                                              mem->memory_size >> PAGE_SHIFT);
-
+       if (change == KVM_MR_CREATE || change == KVM_MR_MOVE)
+               return kvm_alloc_memslot_metadata(memslot,
+                                                 mem->memory_size >> PAGE_SHIFT);
        return 0;
 }