[RFC PATCH 09/10] KVM: selftests: Add tests around sharing a restrictedmem fd

[Ackerley Tng]

Tests that

+ Different memslots in the same VM should be able to share a
  restrictedmem_fd
+ A second VM cannot share the same offsets in a restrictedmem_fd
+ Different VMs should be able to share the same restrictedmem_fd, as
  long as the offsets in the restrictedmem_fd are different

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../selftests/kvm/set_memory_region_test.c    | 29 +++++++++++++++++--
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c 
b/tools/testing/selftests/kvm/set_memory_region_test.c
index cc727d11569e..789c413e2a67 100644
--- a/tools/testing/selftests/kvm/set_memory_region_test.c
+++ b/tools/testing/selftests/kvm/set_memory_region_test.c
@@ -401,7 +401,7 @@ static bool set_private_region_failed(struct kvm_vm *vm, 
void *hva,
 static void test_private_regions(void)
 {
        int ret;
-       struct kvm_vm *vm;
+       struct kvm_vm *vm, *vm2;
        void *mem;
        int fd;
 
@@ -416,7 +416,7 @@ static void test_private_regions(void)
 
        vm = __vm_create(shape, 1, 0);
 
-       mem = mmap(NULL, MEM_REGION_SIZE * 2, PROT_READ | PROT_WRITE,
+       mem = mmap(NULL, MEM_REGION_SIZE * 3, PROT_READ | PROT_WRITE,
                   MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
        TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() host");
 
@@ -448,8 +448,31 @@ static void test_private_regions(void)
        TEST_ASSERT(ret == -1 && errno == EINVAL,
                    "Set overlapping restrictedmem_offset should fail");
 
-       munmap(mem, MEM_REGION_SIZE * 2);
+       ret = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT + 1,
+                                          KVM_MEM_PRIVATE,
+                                          MEM_REGION_GPA + MEM_REGION_SIZE,
+                                          MEM_REGION_SIZE,
+                                          mem + MEM_REGION_SIZE,
+                                          fd, MEM_REGION_SIZE);
+       TEST_ASSERT(!ret,
+                   "Different memslots should be able to share a 
restrictedmem_fd");
+
+       vm2 = __vm_create(shape, 1, 0);
+       TEST_ASSERT(set_private_region_failed(vm2, mem + 2 * MEM_REGION_SIZE, 
fd, 0),
+                   "Pages (offsets) of a restrictedmem_fd should be exclusive 
to a VM");
+
+       ret = __vm_set_user_memory_region2(vm2, MEM_REGION_SLOT,
+                                          KVM_MEM_PRIVATE,
+                                          MEM_REGION_GPA + 2 * MEM_REGION_SIZE,
+                                          MEM_REGION_SIZE,
+                                          mem + 2 * MEM_REGION_SIZE,
+                                          fd, 2 * MEM_REGION_SIZE);
+       TEST_ASSERT(!ret,
+                   "Different VMs should be able to share a restrictedmem_fd");
+
+       munmap(mem, MEM_REGION_SIZE * 3);
        kvm_vm_free(vm);
+       kvm_vm_free(vm2);
 }
 
 int main(int argc, char *argv[])
-- 
2.40.0.rc2.332.ga46443480c-goog