KVM: selftests: Sanity check input to ioctls() at build time

Add a static assert to the KVM/VM/vCPU ioctl() helpers to verify that the
size of the argument provided matches the expected size of the IOCTL.
Because ioctl() ultimately takes a "void *", it's all too easy to pass in
garbage and not detect the error until runtime.  E.g. while working on a
CPUID rework, selftests happily compiled when vcpu_set_cpuid()
unintentionally passed the cpuid() function as the parameter to ioctl()
(a local "cpuid" parameter was removed, but its use was not replaced with
"vcpu->cpuid" as intended).

Tweak a variety of benign issues that aren't compatible with the sanity
check, e.g. passing a non-pointer for ioctls().

Note, static_assert() requires a string on older versions of GCC.  Feed
it an empty string to make the compiler happy.

Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

1 files changed, 2 insertions, 27 deletions

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index cca89d9a83ea..39f2f5f1338f 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -72,7 +72,7 @@ unsigned int kvm_check_cap(long cap)
 	int kvm_fd;
 
 	kvm_fd = open_kvm_dev_path_or_exit();
-	ret = __kvm_ioctl(kvm_fd, KVM_CHECK_EXTENSION, cap);
+	ret = __kvm_ioctl(kvm_fd, KVM_CHECK_EXTENSION, (void *)cap);
 	TEST_ASSERT(ret >= 0, KVM_IOCTL_ERROR(KVM_CHECK_EXTENSION, ret));
 
 	close(kvm_fd);
@@ -92,7 +92,7 @@ static void vm_open(struct kvm_vm *vm)
 
 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_IMMEDIATE_EXIT));
 
-	vm->fd = __kvm_ioctl(vm->kvm_fd, KVM_CREATE_VM, vm->type);
+	vm->fd = __kvm_ioctl(vm->kvm_fd, KVM_CREATE_VM, (void *)vm->type);
 	TEST_ASSERT(vm->fd >= 0, KVM_IOCTL_ERROR(KVM_CREATE_VM, vm->fd));
 }
 
@@ -1450,19 +1450,6 @@ struct kvm_reg_list *vcpu_get_reg_list(struct kvm_vcpu *vcpu)
 	return reg_list;
 }
 
-int __vcpu_ioctl(struct kvm_vcpu *vcpu, unsigned long cmd, void *arg)
-{
-	return ioctl(vcpu->fd, cmd, arg);
-}
-
-void _vcpu_ioctl(struct kvm_vcpu *vcpu, unsigned long cmd, const char *name,
-		 void *arg)
-{
-	int ret = __vcpu_ioctl(vcpu, cmd, arg);
-
-	TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(name, ret));
-}
-
 void *vcpu_map_dirty_ring(struct kvm_vcpu *vcpu)
 {
 	uint32_t page_size = vcpu->vm->page_size;
@@ -1492,18 +1479,6 @@ void *vcpu_map_dirty_ring(struct kvm_vcpu *vcpu)
 	return vcpu->dirty_gfns;
 }
 
-int __vm_ioctl(struct kvm_vm *vm, unsigned long cmd, void *arg)
-{
-	return ioctl(vm->fd, cmd, arg);
-}
-
-void _vm_ioctl(struct kvm_vm *vm, unsigned long cmd, const char *name, void *arg)
-{
-	int ret = __vm_ioctl(vm, cmd, arg);
-
-	TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(name, ret));
-}
-
 /*
  * Device Ioctl
  */