kvmtool: Abstract KVM_VM_TYPE into a weak function

Most architectures pass a fixed value for their VM type. However,
arm64 uses it as a parameter describing the size of the guest's
physical address space.

In order to support this, introduce a kvm__get_vm_type() helper
that only returns KVM_VM_TYPE for now.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Oliver Upton <oupton@google.com>
Link: https://lore.kernel.org/r/20210822152526.1291918-2-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

2 files changed, 7 insertions, 1 deletions

diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h
index 56e9c8e3..ad732e56 100644
--- a/include/kvm/kvm.h
+++ b/include/kvm/kvm.h
@@ -114,6 +114,7 @@ int kvm__init(struct kvm *kvm);
 struct kvm *kvm__new(void);
 int kvm__recommended_cpus(struct kvm *kvm);
 int kvm__max_cpus(struct kvm *kvm);
+int kvm__get_vm_type(struct kvm *kvm);
 void kvm__init_ram(struct kvm *kvm);
 int kvm__exit(struct kvm *kvm);
 bool kvm__load_firmware(struct kvm *kvm, const char *firmware_filename);
diff --git a/kvm.c b/kvm.c
index e327541d..5bc66c8b 100644
--- a/kvm.c
+++ b/kvm.c
@@ -428,6 +428,11 @@ int kvm__max_cpus(struct kvm *kvm)
 	return ret;
 }
 
+int __attribute__((weak)) kvm__get_vm_type(struct kvm *kvm)
+{
+	return KVM_VM_TYPE;
+}
+
 int kvm__init(struct kvm *kvm)
 {
 	int ret;
@@ -461,7 +466,7 @@ int kvm__init(struct kvm *kvm)
 		goto err_sys_fd;
 	}
 
-	kvm->vm_fd = ioctl(kvm->sys_fd, KVM_CREATE_VM, KVM_VM_TYPE);
+	kvm->vm_fd = ioctl(kvm->sys_fd, KVM_CREATE_VM, kvm__get_vm_type(kvm));
 	if (kvm->vm_fd < 0) {
 		pr_err("KVM_CREATE_VM ioctl");
 		ret = kvm->vm_fd;