[PATCH v5 4/9] KVM: selftests: Split out a KVM_CREATE_VCPU helper that can fail

["Ritesh Harjani (IBM)" <ritesh.list@gmail.com>]

__vm_vcpu_add() currently asserts on KVM_CREATE_VCPU, which is what most
callers want. But sometimes a test may want to handle ENOMEM without
dropping all that other setup that __vm_vcpu_add() has.

This patch adds a helper __vm_vcpu_try_add() for such test cases and
make __vm_vcpu_add() a wrapper around that.

Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
---
 .../testing/selftests/kvm/include/kvm_util.h  |  1 +
 tools/testing/selftests/kvm/lib/kvm_util.c    | 26 ++++++++++++++-----
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 9df16c8dc82a..aa521b383abe 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -784,6 +784,7 @@ void vm_mem_region_set_flags(struct kvm_vm *vm, u32 slot, u32 flags);
 void vm_mem_region_reload(struct kvm_vm *vm, u32 slot);
 void vm_mem_region_move(struct kvm_vm *vm, u32 slot, u64 new_gpa);
 void vm_mem_region_delete(struct kvm_vm *vm, u32 slot);
+struct kvm_vcpu *__vm_vcpu_try_add(struct kvm_vm *vm, u32 vcpu_id);
 struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, u32 vcpu_id);
 void vm_populate_gva_bitmap(struct kvm_vm *vm);
 gva_t vm_unused_gva_gap(struct kvm_vm *vm, size_t sz, gva_t min_gva);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 2be79c240ebf..7084ed90e4cc 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1367,11 +1367,7 @@ static bool vcpu_exists(struct kvm_vm *vm, u32 vcpu_id)
 	return false;
 }
 
-/*
- * Adds a virtual CPU to the VM specified by vm with the ID given by vcpu_id.
- * No additional vCPU setup is done.  Returns the vCPU.
- */
-struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, u32 vcpu_id)
+struct kvm_vcpu *__vm_vcpu_try_add(struct kvm_vm *vm, u32 vcpu_id)
 {
 	struct kvm_vcpu *vcpu;
 
@@ -1385,7 +1381,13 @@ struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, u32 vcpu_id)
 	vcpu->vm = vm;
 	vcpu->id = vcpu_id;
 	vcpu->fd = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)(unsigned long)vcpu_id);
-	TEST_ASSERT_VM_VCPU_IOCTL(vcpu->fd >= 0, KVM_CREATE_VCPU, vcpu->fd, vm);
+	if (vcpu->fd < 0) {
+		int __errno = errno;
+
+		free(vcpu);
+		errno = __errno;
+		return NULL;
+	}
 
 	TEST_ASSERT(vcpu_mmap_sz() >= sizeof(*vcpu->run), "vcpu mmap size "
 		"smaller than expected, vcpu_mmap_sz: %zi expected_min: %zi",
@@ -1404,6 +1406,18 @@ struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, u32 vcpu_id)
 	return vcpu;
 }
 
+/*
+ * Adds a virtual CPU to the VM specified by vm with the ID given by vcpu_id.
+ * No additional vCPU setup is done.  Returns the vCPU.
+ */
+struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, u32 vcpu_id)
+{
+	struct kvm_vcpu *vcpu = __vm_vcpu_try_add(vm, vcpu_id);
+
+	TEST_ASSERT_VM_VCPU_IOCTL(vcpu, KVM_CREATE_VCPU, -1, vm);
+	return vcpu;
+}
+
 /*
  * Within the VM specified by @vm, locates the lowest starting guest virtual
  * address >= @min_gva, that has at least @sz unallocated bytes.  A
-- 
2.39.5