selftests/x86/lam: Add io_uring test cases for linear-address masking

LAM should be supported in kernel thread, using io_uring to verify LAM feature.
The test cases implement read a file through io_uring, the test cases choose an
iovec array as receiving buffer, which used to receive data, according to LAM
mode, set metadata in high bits of these buffer.

io_uring can deal with these buffers that pointed to pointers with the metadata
in high bits.
Signed-off-by: Weihong Zhang <weihong.zhang@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230312112612.31869-15-kirill.shutemov%40linux.intel.com

tools/testing/selftests/x86/lam.c

@@ -9,8 +9,12 @@
 #include <sys/mman.h>
 #include <sys/utsname.h>
 #include <sys/wait.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <inttypes.h>
 
+#include <sys/uio.h>
+#include <linux/io_uring.h>
 #include "../kselftest.h"
 
 #ifndef __x86_64__
@@ -32,8 +36,9 @@
 #define FUNC_BITS               0x2
 #define FUNC_MMAP               0x4
 #define FUNC_SYSCALL            0x8
+#define FUNC_URING              0x10
 
-#define TEST_MASK               0xf
+#define TEST_MASK               0x1f
 
 #define LOW_ADDR                (0x1UL << 30)
 #define HIGH_ADDR               (0x3UL << 48)
@@ -42,6 +47,13 @@
 
 #define PAGE_SIZE               (4 << 10)
 
+#define barrier() ({						\
+		   __asm__ __volatile__("" : : : "memory");	\
+})
+
+#define URING_QUEUE_SZ 1
+#define URING_BLOCK_SZ 2048
+
 struct testcases {
 	unsigned int later;
 	int expected; /* 2: SIGSEGV Error; 1: other errors */
@@ -51,6 +63,33 @@ struct testcases {
 	const char *msg;
 };
 
+/* Used by CQ of uring, source file handler and file's size */
+struct file_io {
+	int file_fd;
+	off_t file_sz;
+	struct iovec iovecs[];
+};
+
+struct io_uring_queue {
+	unsigned int *head;
+	unsigned int *tail;
+	unsigned int *ring_mask;
+	unsigned int *ring_entries;
+	unsigned int *flags;
+	unsigned int *array;
+	union {
+		struct io_uring_cqe *cqes;
+		struct io_uring_sqe *sqes;
+	} queue;
+	size_t ring_sz;
+};
+
+struct io_ring {
+	int ring_fd;
+	struct io_uring_queue sq_ring;
+	struct io_uring_queue cq_ring;
+};
+
 int tests_cnt;
 jmp_buf segv_env;
 
@@ -294,6 +333,285 @@ static int handle_syscall(struct testcases *test)
 	return ret;
 }
 
+int sys_uring_setup(unsigned int entries, struct io_uring_params *p)
+{
+	return (int)syscall(__NR_io_uring_setup, entries, p);
+}
+
+int sys_uring_enter(int fd, unsigned int to, unsigned int min, unsigned int flags)
+{
+	return (int)syscall(__NR_io_uring_enter, fd, to, min, flags, NULL, 0);
+}
+
+/* Init submission queue and completion queue */
+int mmap_io_uring(struct io_uring_params p, struct io_ring *s)
+{
+	struct io_uring_queue *sring = &s->sq_ring;
+	struct io_uring_queue *cring = &s->cq_ring;
+
+	sring->ring_sz = p.sq_off.array + p.sq_entries * sizeof(unsigned int);
+	cring->ring_sz = p.cq_off.cqes + p.cq_entries * sizeof(struct io_uring_cqe);
+
+	if (p.features & IORING_FEAT_SINGLE_MMAP) {
+		if (cring->ring_sz > sring->ring_sz)
+			sring->ring_sz = cring->ring_sz;
+
+		cring->ring_sz = sring->ring_sz;
+	}
+
+	void *sq_ptr = mmap(0, sring->ring_sz, PROT_READ | PROT_WRITE,
+			    MAP_SHARED | MAP_POPULATE, s->ring_fd,
+			    IORING_OFF_SQ_RING);
+
+	if (sq_ptr == MAP_FAILED) {
+		perror("sub-queue!");
+		return 1;
+	}
+
+	void *cq_ptr = sq_ptr;
+
+	if (!(p.features & IORING_FEAT_SINGLE_MMAP)) {
+		cq_ptr = mmap(0, cring->ring_sz, PROT_READ | PROT_WRITE,
+			      MAP_SHARED | MAP_POPULATE, s->ring_fd,
+			      IORING_OFF_CQ_RING);
+		if (cq_ptr == MAP_FAILED) {
+			perror("cpl-queue!");
+			munmap(sq_ptr, sring->ring_sz);
+			return 1;
+		}
+	}
+
+	sring->head = sq_ptr + p.sq_off.head;
+	sring->tail = sq_ptr + p.sq_off.tail;
+	sring->ring_mask = sq_ptr + p.sq_off.ring_mask;
+	sring->ring_entries = sq_ptr + p.sq_off.ring_entries;
+	sring->flags = sq_ptr + p.sq_off.flags;
+	sring->array = sq_ptr + p.sq_off.array;
+
+	/* Map a queue as mem map */
+	s->sq_ring.queue.sqes = mmap(0, p.sq_entries * sizeof(struct io_uring_sqe),
+				     PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE,
+				     s->ring_fd, IORING_OFF_SQES);
+	if (s->sq_ring.queue.sqes == MAP_FAILED) {
+		munmap(sq_ptr, sring->ring_sz);
+		if (sq_ptr != cq_ptr) {
+			ksft_print_msg("failed to mmap uring queue!");
+			munmap(cq_ptr, cring->ring_sz);
+			return 1;
+		}
+	}
+
+	cring->head = cq_ptr + p.cq_off.head;
+	cring->tail = cq_ptr + p.cq_off.tail;
+	cring->ring_mask = cq_ptr + p.cq_off.ring_mask;
+	cring->ring_entries = cq_ptr + p.cq_off.ring_entries;
+	cring->queue.cqes = cq_ptr + p.cq_off.cqes;
+
+	return 0;
+}
+
+/* Init io_uring queues */
+int setup_io_uring(struct io_ring *s)
+{
+	struct io_uring_params para;
+
+	memset(&para, 0, sizeof(para));
+	s->ring_fd = sys_uring_setup(URING_QUEUE_SZ, &para);
+	if (s->ring_fd < 0)
+		return 1;
+
+	return mmap_io_uring(para, s);
+}
+
+/*
+ * Get data from completion queue. the data buffer saved the file data
+ * return 0: success; others: error;
+ */
+int handle_uring_cq(struct io_ring *s)
+{
+	struct file_io *fi = NULL;
+	struct io_uring_queue *cring = &s->cq_ring;
+	struct io_uring_cqe *cqe;
+	unsigned int head;
+	off_t len = 0;
+
+	head = *cring->head;
+
+	do {
+		barrier();
+		if (head == *cring->tail)
+			break;
+		/* Get the entry */
+		cqe = &cring->queue.cqes[head & *s->cq_ring.ring_mask];
+		fi = (struct file_io *)cqe->user_data;
+		if (cqe->res < 0)
+			break;
+
+		int blocks = (int)(fi->file_sz + URING_BLOCK_SZ - 1) / URING_BLOCK_SZ;
+
+		for (int i = 0; i < blocks; i++)
+			len += fi->iovecs[i].iov_len;
+
+		head++;
+	} while (1);
+
+	*cring->head = head;
+	barrier();
+
+	return (len != fi->file_sz);
+}
+
+/*
+ * Submit squeue. specify via IORING_OP_READV.
+ * the buffer need to be set metadata according to LAM mode
+ */
+int handle_uring_sq(struct io_ring *ring, struct file_io *fi, unsigned long lam)
+{
+	int file_fd = fi->file_fd;
+	struct io_uring_queue *sring = &ring->sq_ring;
+	unsigned int index = 0, cur_block = 0, tail = 0, next_tail = 0;
+	struct io_uring_sqe *sqe;
+
+	off_t remain = fi->file_sz;
+	int blocks = (int)(remain + URING_BLOCK_SZ - 1) / URING_BLOCK_SZ;
+
+	while (remain) {
+		off_t bytes = remain;
+		void *buf;
+
+		if (bytes > URING_BLOCK_SZ)
+			bytes = URING_BLOCK_SZ;
+
+		fi->iovecs[cur_block].iov_len = bytes;
+
+		if (posix_memalign(&buf, URING_BLOCK_SZ, URING_BLOCK_SZ))
+			return 1;
+
+		fi->iovecs[cur_block].iov_base = (void *)set_metadata((uint64_t)buf, lam);
+		remain -= bytes;
+		cur_block++;
+	}
+
+	next_tail = *sring->tail;
+	tail = next_tail;
+	next_tail++;
+
+	barrier();
+
+	index = tail & *ring->sq_ring.ring_mask;
+
+	sqe = &ring->sq_ring.queue.sqes[index];
+	sqe->fd = file_fd;
+	sqe->flags = 0;
+	sqe->opcode = IORING_OP_READV;
+	sqe->addr = (unsigned long)fi->iovecs;
+	sqe->len = blocks;
+	sqe->off = 0;
+	sqe->user_data = (uint64_t)fi;
+
+	sring->array[index] = index;
+	tail = next_tail;
+
+	if (*sring->tail != tail) {
+		*sring->tail = tail;
+		barrier();
+	}
+
+	if (sys_uring_enter(ring->ring_fd, 1, 1, IORING_ENTER_GETEVENTS) < 0)
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Test LAM in async I/O and io_uring, read current binery through io_uring
+ * Set metadata in pointers to iovecs buffer.
+ */
+int do_uring(unsigned long lam)
+{
+	struct io_ring *ring;
+	struct file_io *fi;
+	struct stat st;
+	int ret = 1;
+	char path[PATH_MAX];
+
+	/* get current process path */
+	if (readlink("/proc/self/exe", path, PATH_MAX) <= 0)
+		return 1;
+
+	int file_fd = open(path, O_RDONLY);
+
+	if (file_fd < 0)
+		return 1;
+
+	if (fstat(file_fd, &st) < 0)
+		return 1;
+
+	off_t file_sz = st.st_size;
+
+	int blocks = (int)(file_sz + URING_BLOCK_SZ - 1) / URING_BLOCK_SZ;
+
+	fi = malloc(sizeof(*fi) + sizeof(struct iovec) * blocks);
+	if (!fi)
+		return 1;
+
+	fi->file_sz = file_sz;
+	fi->file_fd = file_fd;
+
+	ring = malloc(sizeof(*ring));
+	if (!ring)
+		return 1;
+
+	memset(ring, 0, sizeof(struct io_ring));
+
+	if (setup_io_uring(ring))
+		goto out;
+
+	if (handle_uring_sq(ring, fi, lam))
+		goto out;
+
+	ret = handle_uring_cq(ring);
+
+out:
+	free(ring);
+
+	for (int i = 0; i < blocks; i++) {
+		if (fi->iovecs[i].iov_base) {
+			uint64_t addr = ((uint64_t)fi->iovecs[i].iov_base);
+
+			switch (lam) {
+			case LAM_U57_BITS: /* Clear bits 62:57 */
+				addr = (addr & ~(0x3fULL << 57));
+				break;
+			}
+			free((void *)addr);
+			fi->iovecs[i].iov_base = NULL;
+		}
+	}
+
+	free(fi);
+
+	return ret;
+}
+
+int handle_uring(struct testcases *test)
+{
+	int ret = 0;
+
+	if (test->later == 0 && test->lam != 0)
+		if (set_lam(test->lam) != 0)
+			return 1;
+
+	if (sigsetjmp(segv_env, 1) == 0) {
+		signal(SIGSEGV, segv_handler);
+		ret = do_uring(test->lam);
+	} else {
+		ret = 2;
+	}
+
+	return ret;
+}
+
 static int fork_test(struct testcases *test)
 {
 	int ret, child_ret;
@@ -340,6 +658,22 @@ static void run_test(struct testcases *test, int count)
 	}
 }
 
+static struct testcases uring_cases[] = {
+	{
+		.later = 0,
+		.lam = LAM_U57_BITS,
+		.test_func = handle_uring,
+		.msg = "URING: LAM_U57. Dereferencing pointer with metadata\n",
+	},
+	{
+		.later = 1,
+		.expected = 1,
+		.lam = LAM_U57_BITS,
+		.test_func = handle_uring,
+		.msg = "URING:[Negative] Disable LAM. Dereferencing pointer with metadata.\n",
+	},
+};
+
 static struct testcases malloc_cases[] = {
 	{
 		.later = 0,
@@ -410,7 +744,7 @@ static void cmd_help(void)
 {
 	printf("usage: lam [-h] [-t test list]\n");
 	printf("\t-t test list: run tests specified in the test list, default:0x%x\n", TEST_MASK);
-	printf("\t\t0x1:malloc; 0x2:max_bits; 0x4:mmap; 0x8:syscall.\n");
+	printf("\t\t0x1:malloc; 0x2:max_bits; 0x4:mmap; 0x8:syscall; 0x10:io_uring.\n");
 	printf("\t-h: help\n");
 }
 
@@ -456,6 +790,9 @@ int main(int argc, char **argv)
 	if (tests & FUNC_SYSCALL)
 		run_test(syscall_cases, ARRAY_SIZE(syscall_cases));
 
+	if (tests & FUNC_URING)
+		run_test(uring_cases, ARRAY_SIZE(uring_cases));
+
 	ksft_set_plan(tests_cnt);
 
 	return ksft_exit_pass();