[RFC V2 PATCH 4/8] selftests: kvm: priv_memfd_test: Add shared access test

Vishal Annapurve
2022-05-11T00:09:34Z

Add a test to access private memory in shared fashion
which should exercise implicit memory conversion path
using KVM_EXIT_MEMORY_ERROR.

Signed-off-by: Vishal Annapurve <vannapurve@google.com>
---
tools/testing/selftests/kvm/priv_memfd_test.c | 69 +++++++++++++++++++
1 file changed, 69 insertions(+)

diff --git a/tools/testing/selftests/kvm/priv_memfd_test.c b/tools/testing/selftests/kvm/priv_memfd_test.c
index 55e24c893b07..48bc4343e7b5 100644
--- a/tools/testing/selftests/kvm/priv_memfd_test.c
+++ b/tools/testing/selftests/kvm/priv_memfd_test.c
@@ -147,12 +147,81 @@ static void pmpat_guest_code(void)
GUEST_DONE();
}

+/* Test to verify guest shared accesses on private memory with following steps:
+ * 1) Upon entry, guest signals VMM that it has started.
+ * 2) VMM populates the shared memory with known pattern and continues guest
+ * execution.
+ * 3) Guest reads private gpa range in a shared fashion and verifies that it
+ * reads what VMM has written in step2.
+ * 3) Guest writes a different pattern on the shared memory and signals VMM
+ * that it has updated the shared memory.
+ * 4) VMM verifies shared memory contents to be same as the data populated
+ * in step 3 and continues guest execution.
+ */
+#define PMSAT_ID 1
+#define PMSAT_DESC "PrivateMemorySharedAccessTest"
+
+/* Guest code execution stages for private mem access test */
+#define PMSAT_GUEST_STARTED 0ULL
+#define PMSAT_GUEST_TEST_MEM_UPDATED 1ULL
+
+static bool pmsat_handle_vm_stage(struct kvm_vm *vm,
+ void *test_info,
+ uint64_t stage)
+{
+ void *shared_mem = ((struct test_run_helper *)test_info)->shared_mem;
+
+ switch (stage) {
+ case PMSAT_GUEST_STARTED: {
+ /* Initialize the contents of shared memory */
+ TEST_ASSERT(do_mem_op(SET_PAT, shared_mem,
+ TEST_MEM_DATA_PAT1, TEST_MEM_SIZE),
+ "Shared memory update failed");
+ VM_STAGE_PROCESSED(PMSAT_GUEST_STARTED);
+ break;
+ }
+ case PMSAT_GUEST_TEST_MEM_UPDATED: {
+ /* verify data to be same as what guest wrote */
+ TEST_ASSERT(do_mem_op(VERIFY_PAT, shared_mem,
+ TEST_MEM_DATA_PAT2, TEST_MEM_SIZE),
+ "Shared memory view mismatch");
+ VM_STAGE_PROCESSED(PMSAT_GUEST_TEST_MEM_UPDATED);
+ break;
+ }
+ default:
+ printf("Unhandled VM stage %ld\n", stage);
+ return false;
+ }
+
+ return true;
+}
+
+static void pmsat_guest_code(void)
+{
+ void *shared_mem = (void *)TEST_MEM_GPA;
+
+ GUEST_SYNC(PMSAT_GUEST_STARTED);
+ GUEST_ASSERT(do_mem_op(VERIFY_PAT, shared_mem,
+ TEST_MEM_DATA_PAT1, TEST_MEM_SIZE));
+
+ GUEST_ASSERT(do_mem_op(SET_PAT, shared_mem,
+ TEST_MEM_DATA_PAT2, TEST_MEM_SIZE));
+ GUEST_SYNC(PMSAT_GUEST_TEST_MEM_UPDATED);
+
+ GUEST_DONE();
+}
+
static struct test_run_helper priv_memfd_testsuite[] = {
[PMPAT_ID] = {
.test_desc = PMPAT_DESC,
.vmst_handler = pmpat_handle_vm_stage,
.guest_fn = pmpat_guest_code,
},
+ [PMSAT_ID] = {
+ .test_desc = PMSAT_DESC,
+ .vmst_handler = pmsat_handle_vm_stage,
+ .guest_fn = pmsat_guest_code,
+ },
};

static void handle_vm_exit_hypercall(struct kvm_run *run,
--
2.36.0.550.gb090851708-goog