Merge tag 'kvm-x86-gmem-7.2' of https://github.com/kvm-x86/linux into HEAD

KVM guest_memfd changes for 7.2

 - Return -EEXIST instead of -EINVAL if userspace attempts to bind a gmem
   range to multiple memslots, and fix the test that was supposed to ensure
   KVM returns -EEXIST.

 - Treat memslot binding offsets and sizes as unsigned values to fix a bug
   where KVM interprets a large "offset + size" as a negative value and allows
   a nonsensical offset.

 - Use the inode number instead of the page offset for the NUMA interleaving
   index to fix a bug where the effective index would jump by two for
   consecutive pages (the caller also adds in the page offset).

2 files changed, 49 insertions, 6 deletions

diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index 832ef4dfb99f..2233d871a38f 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -345,6 +345,16 @@ static void test_invalid_punch_hole(int fd, size_t total_size)
 	}
 }
 
+static void test_invalid_binding(struct kvm_vm *vm, int fd, size_t size)
+{
+	int r;
+
+	r = __vm_set_user_memory_region2(vm, 0, KVM_MEM_GUEST_MEMFD, 0, size, 0,
+					 fd, ALIGN_DOWN(INT64_MAX, page_size));
+	TEST_ASSERT(r && errno == EINVAL,
+		    "Memslot with out-of-range offset+size should fail");
+}
+
 static void test_create_guest_memfd_invalid_sizes(struct kvm_vm *vm,
 						  u64 guest_memfd_flags)
 {
@@ -408,17 +418,26 @@ static void test_guest_memfd_flags(struct kvm_vm *vm)
 	}
 }
 
-#define __gmem_test(__test, __vm, __flags, __gmem_size)			\
+#define ____gmem_test(__test, __vm, __flags, __gmem_size, args...)	\
 do {									\
 	int fd = vm_create_guest_memfd(__vm, __gmem_size, __flags);	\
 									\
-	test_##__test(fd, __gmem_size);					\
+	test_##__test(args);						\
 	close(fd);							\
 } while (0)
 
+#define __gmem_test(__test, __vm, __flags, __gmem_size)			\
+	____gmem_test(__test, __vm, __flags, __gmem_size, fd, __gmem_size)
+
 #define gmem_test(__test, __vm, __flags)				\
 	__gmem_test(__test, __vm, __flags, page_size * 4)
 
+#define __gmem_test_vm(__test, __vm, __flags, __gmem_size)		\
+	____gmem_test(__test, __vm, __flags, __gmem_size, __vm, fd, __gmem_size)
+
+#define gmem_test_vm(__test, __vm, __flags)				\
+	__gmem_test_vm(__test, __vm, __flags, page_size * 4)
+
 static void __test_guest_memfd(struct kvm_vm *vm, u64 flags)
 {
 	test_create_guest_memfd_multiple(vm);
@@ -447,6 +466,7 @@ static void __test_guest_memfd(struct kvm_vm *vm, u64 flags)
 	gmem_test(file_size, vm, flags);
 	gmem_test(fallocate, vm, flags);
 	gmem_test(invalid_punch_hole, vm, flags);
+	gmem_test_vm(invalid_binding, vm, flags);
 }
 
 static void test_guest_memfd(unsigned long vm_type)
diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c b/tools/testing/selftests/kvm/set_memory_region_test.c
index e639a9db51ee..a152ab65c657 100644
--- a/tools/testing/selftests/kvm/set_memory_region_test.c
+++ b/tools/testing/selftests/kvm/set_memory_region_test.c
@@ -510,7 +510,7 @@ static void test_add_overlapping_private_memory_regions(void)
 
 	vm = vm_create_barebones_type(KVM_X86_SW_PROTECTED_VM);
 
-	memfd = vm_create_guest_memfd(vm, MEM_REGION_SIZE * 4, 0);
+	memfd = vm_create_guest_memfd(vm, MEM_REGION_SIZE * 5, 0);
 
 	vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
 				   MEM_REGION_GPA, MEM_REGION_SIZE * 2, 0, memfd, 0);
@@ -526,12 +526,35 @@ static void test_add_overlapping_private_memory_regions(void)
 	vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
 				   MEM_REGION_GPA, 0, NULL, -1, 0);
 
-	/* Overlap the front half of the other slot. */
+	/*
+	 * Verify that overlap in the guest_memfd bindings (i.e. in guest_memfd
+	 * file offsets), but _not_ in the GPA space, fails with -EEXIST.
+	 */
+	r = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
+					 MEM_REGION_GPA,
+					 MEM_REGION_SIZE * 2,
+					 0, memfd, MEM_REGION_SIZE);
+	TEST_ASSERT(r == -1 && errno == EEXIST,
+		    "Overlapping guest_memfd() bindings should fail with EEXIST");
+
+	/* And now the back half of the other slot's guest_memfd binding. */
+	r = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
+					 MEM_REGION_GPA,
+					 MEM_REGION_SIZE * 2,
+					 0, memfd, MEM_REGION_SIZE * 3);
+	TEST_ASSERT(r == -1 && errno == EEXIST,
+		    "Overlapping guest_memfd() bindings should fail with EEXIST");
+
+	/*
+	 * Repeat the overlap tests, but this time with overlap in the memslots
+	 * GPA space.  Regardless of where there is overlap, KVM should return
+	 * -EEXIST.
+	 */
 	r = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
 					 MEM_REGION_GPA * 2 - MEM_REGION_SIZE,
 					 MEM_REGION_SIZE * 2,
 					 0, memfd, 0);
-	TEST_ASSERT(r == -1 && errno == EEXIST, "%s",
+	TEST_ASSERT(r == -1 && errno == EEXIST,
 		    "Overlapping guest_memfd() bindings should fail with EEXIST");
 
 	/* And now the back half of the other slot. */
@@ -539,7 +562,7 @@ static void test_add_overlapping_private_memory_regions(void)
 					 MEM_REGION_GPA * 2 + MEM_REGION_SIZE,
 					 MEM_REGION_SIZE * 2,
 					 0, memfd, 0);
-	TEST_ASSERT(r == -1 && errno == EEXIST, "%s",
+	TEST_ASSERT(r == -1 && errno == EEXIST,
 		    "Overlapping guest_memfd() bindings should fail with EEXIST");
 
 	close(memfd);