[PATCH RFC v2 30/50] KVM: selftests: Add basic test for sample memory provider

[Ackerley Tng via B4 Relay <devnull+ackerleytng.google.com@kernel.org>]

From: Ackerley Tng <ackerleytng@google.com>

Add a selftest for the sample memory provider (/dev/mem_provider_sample).

Test basic lifecycle creation across multiple sizes. Verify file capacity
and absent pages accounting using the MPS_GET_STATS ioctl. Also test
marking pages absent and present with MPS_SET_PRESENT, verifying that
absent pages are reflected in stats accordingly.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/Makefile.kvm           |   1 +
 .../selftests/kvm/mem_provider_sample_test.c       | 147 +++++++++++++++++++++
 2 files changed, 148 insertions(+)

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 17a4256e90819..5f7118bddfc36 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -72,6 +72,7 @@ TEST_GEN_PROGS_COMMON += set_memory_region_test
 TEST_GEN_PROGS_COMMON += memslot_modification_stress_test
 TEST_GEN_PROGS_COMMON += memslot_perf_test
 TEST_GEN_PROGS_COMMON += vm_types_test
+TEST_GEN_PROGS_COMMON += mem_provider_sample_test
 
 # Compiled test targets
 TEST_GEN_PROGS_x86 = $(TEST_GEN_PROGS_COMMON)
diff --git a/tools/testing/selftests/kvm/mem_provider_sample_test.c b/tools/testing/selftests/kvm/mem_provider_sample_test.c
new file mode 100644
index 0000000000000..932ea3f30f494
--- /dev/null
+++ b/tools/testing/selftests/kvm/mem_provider_sample_test.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Tests for the sample memory provider (/dev/mem_provider_sample).
+ */
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "test_util.h"
+#include "../../../../samples/kvm/mem_provider_sample.h"
+
+#define DEV_PATH "/dev/mem_provider_sample"
+
+static int open_provider_dev(void)
+{
+	int fd = open(DEV_PATH, O_RDWR);
+
+	if (fd < 0) {
+		TEST_REQUIRE(errno != ENOENT && errno != ENODEV);
+		TEST_FAIL("Failed to open %s: %d (%s)", DEV_PATH, errno,
+			  strerror(errno));
+	}
+	return fd;
+}
+
+static int create_provider_file(int dev_fd, uint64_t size)
+{
+	struct mps_new_file nf = {
+		.size = size,
+	};
+	int fd;
+
+	fd = ioctl(dev_fd, MPS_NEW_FILE, &nf);
+	TEST_ASSERT(fd >= 0, "MPS_NEW_FILE failed for size 0x%lx: %d (%s)",
+		    size, errno, strerror(errno));
+	return fd;
+}
+
+static void test_lifecycle_and_creation(int dev_fd)
+{
+	size_t page_size = getpagesize();
+	uint64_t sizes[] = {
+		page_size,
+		2 * page_size,
+		2 * 1024 * 1024,
+	};
+	struct mps_stats st;
+	int i, fd;
+
+	for (i = 0; i < ARRAY_SIZE(sizes); i++) {
+		fd = create_provider_file(dev_fd, sizes[i]);
+
+		memset(&st, 0, sizeof(st));
+		TEST_ASSERT(!ioctl(fd, MPS_GET_STATS, &st),
+			    "MPS_GET_STATS failed: %d (%s)",
+			    errno, strerror(errno));
+		TEST_ASSERT(st.size == sizes[i],
+			    "size mismatch: expected 0x%lx, got 0x%llx",
+			    sizes[i], st.size);
+		TEST_ASSERT(st.absent_pages == 0,
+			    "absent_pages mismatch: expected 0, got %llu",
+			    st.absent_pages);
+
+		close(fd);
+	}
+}
+
+static void test_set_present(int dev_fd)
+{
+	size_t page_size = getpagesize();
+	uint64_t nr_pages = 4;
+	uint64_t file_size = nr_pages * page_size;
+	struct mps_set_present sp;
+	struct mps_stats st;
+	int ret, fd;
+
+	fd = create_provider_file(dev_fd, file_size);
+
+	/* Initially all pages are present */
+	TEST_ASSERT(!ioctl(fd, MPS_GET_STATS, &st),
+		    "MPS_GET_STATS failed: %d (%s)", errno, strerror(errno));
+	TEST_ASSERT(st.absent_pages == 0,
+		    "Initial absent_pages mismatch: expected 0, got %llu",
+		    st.absent_pages);
+
+	/* Mark page 1 absent */
+	memset(&sp, 0, sizeof(sp));
+	sp.value = 0;
+	sp.offset = page_size;
+	sp.len = page_size;
+	ret = ioctl(fd, MPS_SET_PRESENT, &sp);
+	TEST_ASSERT(!ret, "MPS_SET_PRESENT (absent) failed: %d (%s)",
+		    errno, strerror(errno));
+
+	TEST_ASSERT(!ioctl(fd, MPS_GET_STATS, &st),
+		    "MPS_GET_STATS failed: %d (%s)", errno, strerror(errno));
+	TEST_ASSERT(st.size == file_size,
+		    "size changed unexpectedly: 0x%llx", st.size);
+	TEST_ASSERT(st.absent_pages == 1,
+		    "absent_pages mismatch after absent: expected 1, got %llu",
+		    st.absent_pages);
+
+	/* Mark page 1 back to present */
+	sp.value = 1;
+	ret = ioctl(fd, MPS_SET_PRESENT, &sp);
+	TEST_ASSERT(!ret, "MPS_SET_PRESENT (present) failed: %d (%s)",
+		    errno, strerror(errno));
+
+	TEST_ASSERT(!ioctl(fd, MPS_GET_STATS, &st),
+		    "MPS_GET_STATS failed: %d (%s)", errno, strerror(errno));
+	TEST_ASSERT(st.absent_pages == 0,
+		    "absent_pages mismatch after restore: expected 0, got %llu",
+		    st.absent_pages);
+
+	/* Mark all pages absent */
+	sp.value = 0;
+	sp.offset = 0;
+	sp.len = file_size;
+	ret = ioctl(fd, MPS_SET_PRESENT, &sp);
+	TEST_ASSERT(!ret, "MPS_SET_PRESENT (all absent) failed: %d (%s)",
+		    errno, strerror(errno));
+
+	TEST_ASSERT(!ioctl(fd, MPS_GET_STATS, &st),
+		    "MPS_GET_STATS failed: %d (%s)", errno, strerror(errno));
+	TEST_ASSERT(st.absent_pages == nr_pages,
+		    "absent_pages mismatch after all absent: expected %lu, got %llu",
+		    nr_pages, st.absent_pages);
+
+	close(fd);
+}
+
+int main(int argc, char *argv[])
+{
+	int dev_fd;
+
+	dev_fd = open_provider_dev();
+
+	test_lifecycle_and_creation(dev_fd);
+	test_set_present(dev_fd);
+
+	close(dev_fd);
+	return 0;
+}

-- 
2.56.0.257.gf7497c7d27-goog