[RFC PATCH 2/6] udmabuf: try udmabuf vmap test

[Huan Yang <link@vivo.com>]

This patch add a test ioctl in udmabuf to show vmap can work.
by compare pfn vmap and pages vmap.

But this skip HVO folio compare due to can't use pages vmap.

Signed-off-by: Huan Yang <link@vivo.com>
---
 drivers/dma-buf/udmabuf.c                     |  71 ++++++++
 include/uapi/linux/udmabuf.h                  |   5 +
 .../selftests/drivers/dma-buf/Makefile        |   1 +
 .../selftests/drivers/dma-buf/udmabuf_vmap.c  | 166 ++++++++++++++++++
 4 files changed, 243 insertions(+)
 create mode 100644 tools/testing/selftests/drivers/dma-buf/udmabuf_vmap.c

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 2dfe639230dc..fbe4b59b4c97 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -557,6 +557,74 @@ static long udmabuf_ioctl_create_list(struct file *filp, unsigned long arg)
 	return ret;
 }
 
+static long udmabuf_vmap_test(struct file *filp, unsigned long arg)
+{
+	struct udmabuf_vmap uv;
+	struct dma_buf *dmabuf;
+	bool can_page = true;
+	struct iosys_map map;
+	struct udmabuf *ubuf;
+	struct page **pages;
+	void *vaddr, *pvaddr;
+	struct file *file;
+	int ret = 0, i;
+
+	if (copy_from_user(&uv, (void __user *)arg, sizeof(uv)))
+		return -EFAULT;
+	file = fget(uv.dma_buf_fd);
+	if (!file)
+		return -EINVAL;
+
+	dmabuf = file->private_data;
+	ret = dma_buf_vmap(dmabuf, &map);
+	if (ret)
+		goto out;
+	vaddr = map.vaddr;
+
+	ubuf = dmabuf->priv;
+	for (i = 0; i < ubuf->pagecount; ++i) {
+		struct folio *folio = ubuf->folios[i];
+
+		if (folio_test_hugetlb_vmemmap_optimized(folio)) {
+			can_page = false;
+			break;
+		}
+	}
+
+	if (!can_page)
+		goto out_vaddr;
+
+	pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages), GFP_KERNEL);
+	if (WARN_ON(!pages)) {
+		ret = -ENOMEM;
+		goto out_vaddr;
+	}
+
+	for (i = 0; i < ubuf->pagecount; ++i)
+		pages[i] = folio_page(ubuf->folios[i],
+				      ubuf->offsets[i] >> PAGE_SHIFT);
+
+	pvaddr = vmap(pages, ubuf->pagecount, 0, PAGE_KERNEL);
+	if (WARN_ON(!pvaddr)) {
+		ret = -ENOMEM;
+		goto out_pages;
+	}
+
+	// compare if pages and pfns is same?
+	if (WARN_ON(memcmp(vaddr, pvaddr, ubuf->pagecount * PAGE_SIZE) != 0))
+		ret = -EINVAL;
+
+	vunmap(pvaddr);
+out_pages:
+	kvfree(pages);
+out_vaddr:
+	dma_buf_vunmap(dmabuf, &map);
+out:
+	fput(file);
+
+	return ret;
+}
+
 static long udmabuf_ioctl(struct file *filp, unsigned int ioctl,
 			  unsigned long arg)
 {
@@ -569,6 +637,9 @@ static long udmabuf_ioctl(struct file *filp, unsigned int ioctl,
 	case UDMABUF_CREATE_LIST:
 		ret = udmabuf_ioctl_create_list(filp, arg);
 		break;
+	case UDMABUF_VMAP:
+		ret = udmabuf_vmap_test(filp, arg);
+		break;
 	default:
 		ret = -ENOTTY;
 		break;
diff --git a/include/uapi/linux/udmabuf.h b/include/uapi/linux/udmabuf.h
index 46b6532ed855..88f5e5516286 100644
--- a/include/uapi/linux/udmabuf.h
+++ b/include/uapi/linux/udmabuf.h
@@ -27,7 +27,12 @@ struct udmabuf_create_list {
 	struct udmabuf_create_item list[];
 };
 
+struct udmabuf_vmap {
+	int dma_buf_fd;
+};
+
 #define UDMABUF_CREATE       _IOW('u', 0x42, struct udmabuf_create)
 #define UDMABUF_CREATE_LIST  _IOW('u', 0x43, struct udmabuf_create_list)
+#define UDMABUF_VMAP  _IOW('u', 0x44, struct udmabuf_vmap)
 
 #endif /* _UAPI_LINUX_UDMABUF_H */
diff --git a/tools/testing/selftests/drivers/dma-buf/Makefile b/tools/testing/selftests/drivers/dma-buf/Makefile
index 441407bb0e80..e5b131dcc2c3 100644
--- a/tools/testing/selftests/drivers/dma-buf/Makefile
+++ b/tools/testing/selftests/drivers/dma-buf/Makefile
@@ -2,6 +2,7 @@
 CFLAGS += $(KHDR_INCLUDES)
 
 TEST_GEN_PROGS := udmabuf
+TEST_GEN_PROGS := udmabuf_vmap
 
 top_srcdir ?=../../../../..
 
diff --git a/tools/testing/selftests/drivers/dma-buf/udmabuf_vmap.c b/tools/testing/selftests/drivers/dma-buf/udmabuf_vmap.c
new file mode 100644
index 000000000000..7bd46c909bdf
--- /dev/null
+++ b/tools/testing/selftests/drivers/dma-buf/udmabuf_vmap.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#define __EXPORTED_HEADERS__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <malloc.h>
+#include <stdbool.h>
+
+#include <sys/ioctl.h>
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <linux/memfd.h>
+#include <linux/udmabuf.h>
+#include "../../kselftest.h"
+
+#define TEST_PREFIX "drivers/dma-buf/udmabuf"
+#define NUM_PAGES 4
+#define NUM_ENTRIES 4
+#define MEMFD_SIZE 1024 /* in pages */
+
+static unsigned int page_size;
+
+static int create_memfd_with_seals(off64_t size, bool hpage)
+{
+	int memfd, ret;
+	unsigned int flags = MFD_ALLOW_SEALING;
+
+	if (hpage)
+		flags |= MFD_HUGETLB;
+
+	memfd = memfd_create("udmabuf-test", flags);
+	if (memfd < 0) {
+		ksft_print_msg("%s: [skip,no-memfd]\n", TEST_PREFIX);
+		exit(KSFT_SKIP);
+	}
+
+	ret = fcntl(memfd, F_ADD_SEALS, F_SEAL_SHRINK);
+	if (ret < 0) {
+		ksft_print_msg("%s: [skip,fcntl-add-seals]\n", TEST_PREFIX);
+		exit(KSFT_SKIP);
+	}
+
+	ret = ftruncate(memfd, size);
+	if (ret == -1) {
+		ksft_print_msg("%s: [FAIL,memfd-truncate]\n", TEST_PREFIX);
+		exit(KSFT_FAIL);
+	}
+
+	return memfd;
+}
+
+static int create_udmabuf_list(int devfd, int memfd, off64_t memfd_size)
+{
+	struct udmabuf_create_list *list;
+	int ubuf_fd, i;
+
+	list = malloc(sizeof(struct udmabuf_create_list) +
+		      sizeof(struct udmabuf_create_item) * NUM_ENTRIES);
+	if (!list) {
+		ksft_print_msg("%s: [FAIL, udmabuf-malloc]\n", TEST_PREFIX);
+		exit(KSFT_FAIL);
+	}
+
+	for (i = 0; i < NUM_ENTRIES; i++) {
+		list->list[i].memfd = memfd;
+		list->list[i].offset = i * (memfd_size / NUM_ENTRIES);
+		list->list[i].size = memfd_size / NUM_ENTRIES;
+	}
+
+	list->count = NUM_ENTRIES;
+	list->flags = UDMABUF_FLAGS_CLOEXEC;
+	ubuf_fd = ioctl(devfd, UDMABUF_CREATE_LIST, list);
+	free(list);
+	if (ubuf_fd < 0) {
+		ksft_print_msg("%s: [FAIL, udmabuf-create]\n", TEST_PREFIX);
+		exit(KSFT_FAIL);
+	}
+
+	return ubuf_fd;
+}
+
+static void *mmap_fd(int fd, off64_t size)
+{
+	void *addr;
+
+	addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if (addr == MAP_FAILED) {
+		ksft_print_msg("%s: ubuf_fd mmap fail\n", TEST_PREFIX);
+		exit(KSFT_FAIL);
+	}
+
+	return addr;
+}
+
+int main(int argc, char *argv[])
+{
+	struct udmabuf_create create;
+	int devfd, memfd, buf, ret;
+	struct udmabuf_vmap vm;
+	unsigned long *vaddr;
+	off64_t size;
+	int i;
+
+	ksft_print_header();
+	ksft_set_plan(2);
+
+	devfd = open("/dev/udmabuf", O_RDWR);
+	if (devfd < 0) {
+		ksft_print_msg(
+			"%s: [skip,no-udmabuf: Unable to access DMA buffer device file]\n",
+			TEST_PREFIX);
+		exit(KSFT_SKIP);
+	}
+
+	/**
+	 * Normal test
+	 */
+	size = getpagesize() * 512 + getpagesize() * 256;
+	memfd = create_memfd_with_seals(size, false);
+	buf = create_udmabuf_list(devfd, memfd, size);
+	vaddr = (unsigned long *)mmap_fd(buf, size);
+	for (i = 0; i < size / sizeof(unsigned long); i++)
+		vaddr[i] = random();
+
+	vm.dma_buf_fd = buf;
+
+	ret = ioctl(devfd, UDMABUF_VMAP, &vm);
+	if (ret < 0)
+		ksft_test_result_fail("%s: [FAIL, normal test]\n", TEST_PREFIX);
+	else
+		ksft_test_result_pass("%s: [PASS, normal test]\n", TEST_PREFIX);
+	munmap(vaddr, size);
+	close(buf);
+	close(memfd);
+
+	/**
+	 * Hugetlb test, 2MB
+	 */
+	size = getpagesize() * 512;
+	memfd = create_memfd_with_seals(size, true);
+	buf = create_udmabuf_list(devfd, memfd, size);
+	vaddr = (unsigned long *)mmap_fd(buf, size);
+	for (i = 0; i < size / sizeof(unsigned long); i++)
+		vaddr[i] = random();
+
+	vm.dma_buf_fd = buf;
+
+	ret = ioctl(devfd, UDMABUF_VMAP, &vm);
+	if (ret < 0)
+		ksft_test_result_fail("%s: [FAIL, huge test]\n", TEST_PREFIX);
+	else
+		ksft_test_result_pass("%s: [PASS, huge test]\n", TEST_PREFIX);
+	munmap(vaddr, size);
+	close(buf);
+	close(memfd);
+
+	ksft_print_msg("%s: ok\n", TEST_PREFIX);
+	ksft_print_cnts();
+
+	return 0;
+}
-- 
2.48.1