KVM: selftests: Require KVM_CAP_USER_MEMORY2 for tests that create memslots

Explicitly require KVM_CAP_USER_MEMORY2 for selftests that create memslots,
i.e. skip selftests that need memslots instead of letting them fail on
KVM_SET_USER_MEMORY_REGION2.  While it's ok to take a dependency on new
kernel features, selftests should skip gracefully instead of failing hard
when run on older kernels.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/69ae0694-8ca3-402c-b864-99b500b24f5d@moroto.mountain
Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240430162133.337541-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index b2262b5fad9e79a509f9c686e675baf2b95b00a0..a24bba9e03907ece96e950abc37c3b237e39293b 100644 (file)
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -930,6 +930,10 @@ void vm_set_user_memory_region(struct kvm_vm *vm, uint32_t slot, uint32_t flags,
                    errno, strerror(errno));
 }
 
+#define TEST_REQUIRE_SET_USER_MEMORY_REGION2()                 \
+       __TEST_REQUIRE(kvm_has_cap(KVM_CAP_USER_MEMORY2),       \
+                      "KVM selftests now require KVM_SET_USER_MEMORY_REGION2 (introduced in v6.8)")
+
 int __vm_set_user_memory_region2(struct kvm_vm *vm, uint32_t slot, uint32_t flags,
                                 uint64_t gpa, uint64_t size, void *hva,
                                 uint32_t guest_memfd, uint64_t guest_memfd_offset)
@@ -944,6 +948,8 @@ int __vm_set_user_memory_region2(struct kvm_vm *vm, uint32_t slot, uint32_t flag
                .guest_memfd_offset = guest_memfd_offset,
        };
 
+       TEST_REQUIRE_SET_USER_MEMORY_REGION2();
+
        return ioctl(vm->fd, KVM_SET_USER_MEMORY_REGION2, &region);
 }
 
@@ -970,6 +976,8 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
        size_t mem_size = npages * vm->page_size;
        size_t alignment;
 
+       TEST_REQUIRE_SET_USER_MEMORY_REGION2();
+
        TEST_ASSERT(vm_adjust_num_guest_pages(vm->mode, npages) == npages,
                "Number of guest pages is not compatible with the host. "
                "Try npages=%d", vm_adjust_num_guest_pages(vm->mode, npages));