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

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Date:   Thu, 16 Mar 2023 00:31:02 +0000
From:   Ackerley Tng <ackerleytng@...gle.com>
To:     kvm@...r.kernel.org, linux-api@...r.kernel.org,
        linux-arch@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, qemu-devel@...gnu.org
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        Ackerley Tng <ackerleytng@...gle.com>
Subject: [RFC PATCH 09/10] KVM: selftests: Add tests around sharing a
 restrictedmem fd

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@...gle.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