KVM: selftests: Extend VM creation's @shape to allow control of VM subtype

Carve out space in the @shape passed to the various VM creation helpers to
allow using the shape to control the subtype of VM, e.g. to identify x86's
SEV VMs (which are "regular" VMs as far as KVM is concerned).

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Tested-by: Carlos Bilbao <carlos.bilbao@amd.com>
Link: https://lore.kernel.org/r/20240223004258.3104051-2-seanjc@google.comSigned-off-by: Sean Christopherson <seanjc@google.com>

tools/testing/selftests/kvm/include/kvm_util_base.h

@@ -90,6 +90,7 @@ enum kvm_mem_region_type {
 struct kvm_vm {
 	int mode;
 	unsigned long type;
+	uint8_t subtype;
 	int kvm_fd;
 	int fd;
 	unsigned int pgtable_levels;
@@ -191,10 +192,14 @@ enum vm_guest_mode {
 };
 
 struct vm_shape {
-	enum vm_guest_mode mode;
-	unsigned int type;
+	uint32_t type;
+	uint8_t  mode;
+	uint8_t  subtype;
+	uint16_t padding;
 };
 
+kvm_static_assert(sizeof(struct vm_shape) == sizeof(uint64_t));
+
 #define VM_TYPE_DEFAULT			0
 
 #define VM_SHAPE(__mode)			\

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -225,6 +225,7 @@ struct kvm_vm *____vm_create(struct vm_shape shape)
 
 	vm->mode = shape.mode;
 	vm->type = shape.type;
+	vm->subtype = shape.subtype;
 
 	vm->pa_bits = vm_guest_mode_params[vm->mode].pa_bits;
 	vm->va_bits = vm_guest_mode_params[vm->mode].va_bits;