[PATCHv11 14/16] selftests/x86/lam: Add io_uring test cases for linear-address masking

From: Kirill A. Shutemov
Date: Mon Oct 24 2022 - 21:09:44 EST


From: Weihong Zhang <weihong.zhang@xxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
tools/testing/selftests/x86/lam.c | 341 +++++++++++++++++++++++++++++-
1 file changed, 339 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c
index cdc6e40e00e0..8ea1fcef4c9f 100644
--- a/tools/testing/selftests/x86/lam.c
+++ b/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();
--
2.38.0