Re: [PATCH i-g-t] igt/gem_userptr: Check read-only mappings

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 27/06/2018 20:44, Chris Wilson wrote:
Setup a userptr object that only has a read-only mapping back to a file
store (memfd). Then attempt to write into that mapping using the GPU and
assert that those writes do not land (while also writing via a writable
userptr mapping into the same memfd to verify that the GPU is working!)

Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
  configure.ac              |   1 +
  lib/ioctl_wrappers.c      |   4 +-
  lib/ioctl_wrappers.h      |   4 +-
  lib/meson.build           |   1 +
  meson.build               |   1 +
  tests/Makefile.am         |   4 +-
  tests/gem_userptr_blits.c | 337 +++++++++++++++++++++++++++++++++++++-
  7 files changed, 342 insertions(+), 10 deletions(-)

diff --git a/configure.ac b/configure.ac
index 1ee4e90e9..195963d4f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -125,6 +125,7 @@ PKG_CHECK_MODULES(PCIACCESS, [pciaccess >= 0.10])
  PKG_CHECK_MODULES(KMOD, [libkmod])
  PKG_CHECK_MODULES(PROCPS, [libprocps])
  PKG_CHECK_MODULES(LIBUNWIND, [libunwind])
+PKG_CHECK_MODULES(SSL, [openssl])
  PKG_CHECK_MODULES(VALGRIND, [valgrind], [have_valgrind=yes], [have_valgrind=no])
if test x$have_valgrind = xyes; then
diff --git a/lib/ioctl_wrappers.c b/lib/ioctl_wrappers.c
index 79db44a8c..d5d2a4e4c 100644
--- a/lib/ioctl_wrappers.c
+++ b/lib/ioctl_wrappers.c
@@ -869,7 +869,7 @@ int gem_madvise(int fd, uint32_t handle, int state)
  	return madv.retained;
  }
-int __gem_userptr(int fd, void *ptr, int size, int read_only, uint32_t flags, uint32_t *handle)
+int __gem_userptr(int fd, void *ptr, uint64_t size, int read_only, uint32_t flags, uint32_t *handle)
  {
  	struct drm_i915_gem_userptr userptr;
@@ -898,7 +898,7 @@ int __gem_userptr(int fd, void *ptr, int size, int read_only, uint32_t flags, ui
   *
   * Returns userptr handle for the GEM object.
   */
-void gem_userptr(int fd, void *ptr, int size, int read_only, uint32_t flags, uint32_t *handle)
+void gem_userptr(int fd, void *ptr, uint64_t size, int read_only, uint32_t flags, uint32_t *handle)
  {
  	igt_assert_eq(__gem_userptr(fd, ptr, size, read_only, flags, handle), 0);
  }
diff --git a/lib/ioctl_wrappers.h b/lib/ioctl_wrappers.h
index b966f72c9..8e2cd380b 100644
--- a/lib/ioctl_wrappers.h
+++ b/lib/ioctl_wrappers.h
@@ -133,8 +133,8 @@ struct local_i915_gem_userptr {
  #define LOCAL_I915_USERPTR_UNSYNCHRONIZED (1<<31)
  	uint32_t handle;
  };
-void gem_userptr(int fd, void *ptr, int size, int read_only, uint32_t flags, uint32_t *handle);
-int __gem_userptr(int fd, void *ptr, int size, int read_only, uint32_t flags, uint32_t *handle);
+void gem_userptr(int fd, void *ptr, uint64_t size, int read_only, uint32_t flags, uint32_t *handle);
+int __gem_userptr(int fd, void *ptr, uint64_t size, int read_only, uint32_t flags, uint32_t *handle);
void gem_sw_finish(int fd, uint32_t handle); diff --git a/lib/meson.build b/lib/meson.build
index 1a355414e..939167f91 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -62,6 +62,7 @@ lib_deps = [
  	pthreads,
  	math,
  	realtime,
+	ssl,
  ]
if libdrm_intel.found()
diff --git a/meson.build b/meson.build
index 4d15d6238..638c01066 100644
--- a/meson.build
+++ b/meson.build
@@ -98,6 +98,7 @@ pciaccess = dependency('pciaccess', version : '>=0.10')
  libkmod = dependency('libkmod')
  libprocps = dependency('libprocps', required : true)
  libunwind = dependency('libunwind', required : true)
+ssl = dependency('openssl', required : true)
valgrind = null_dep
  valgrindinfo = 'No'
diff --git a/tests/Makefile.am b/tests/Makefile.am
index f41ad5096..ba307b220 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -126,8 +126,8 @@ gem_tiled_swapping_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
  gem_tiled_swapping_LDADD = $(LDADD) -lpthread
  prime_self_import_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
  prime_self_import_LDADD = $(LDADD) -lpthread
-gem_userptr_blits_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
-gem_userptr_blits_LDADD = $(LDADD) -lpthread
+gem_userptr_blits_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS) $(SSL_CFLAGS)
+gem_userptr_blits_LDADD = $(LDADD) $(SSL_LIBS) -lpthread
  perf_pmu_LDADD = $(LDADD) $(top_builddir)/lib/libigt_perf.la
gem_eio_LDADD = $(LDADD) -lrt
diff --git a/tests/gem_userptr_blits.c b/tests/gem_userptr_blits.c
index 7e3b6ef38..30c6bc48c 100644
--- a/tests/gem_userptr_blits.c
+++ b/tests/gem_userptr_blits.c
@@ -43,13 +43,17 @@
  #include <fcntl.h>
  #include <inttypes.h>
  #include <errno.h>
+#include <setjmp.h>
  #include <sys/stat.h>
  #include <sys/time.h>
  #include <sys/mman.h>
+#include <openssl/sha.h>
  #include <signal.h>
  #include <pthread.h>
  #include <time.h>
+#include <linux/memfd.h>
+
  #include "drm.h"
  #include "i915_drm.h"
@@ -238,6 +242,57 @@ blit(int fd, uint32_t dst, uint32_t src, uint32_t *all_bo, int n_bo)
  	return ret;
  }
+static void store_dword(int fd, uint32_t target,
+			uint32_t offset, uint32_t value)
+{
+	const int gen = intel_gen(intel_get_drm_devid(fd));
+	struct drm_i915_gem_exec_object2 obj[2];
+	struct drm_i915_gem_relocation_entry reloc;
+	struct drm_i915_gem_execbuffer2 execbuf;
+	uint32_t batch[16];
+	int i;
+
+	memset(&execbuf, 0, sizeof(execbuf));
+	execbuf.buffers_ptr = to_user_pointer(obj);
+	execbuf.buffer_count = ARRAY_SIZE(obj);
+	execbuf.flags = 0;
+	if (gen < 6)
+		execbuf.flags |= I915_EXEC_SECURE;
+
+	memset(obj, 0, sizeof(obj));
+	obj[0].handle = target;
+	obj[1].handle = gem_create(fd, 4096);
+
+	memset(&reloc, 0, sizeof(reloc));
+	reloc.target_handle = obj[0].handle;
+	reloc.presumed_offset = 0;
+	reloc.offset = sizeof(uint32_t);
+	reloc.delta = offset;
+	reloc.read_domains = I915_GEM_DOMAIN_RENDER;
+	reloc.write_domain = I915_GEM_DOMAIN_RENDER;
+	obj[1].relocs_ptr = to_user_pointer(&reloc);
+	obj[1].relocation_count = 1;
+
+	i = 0;
+	batch[i] = MI_STORE_DWORD_IMM | (gen < 6 ? 1 << 22 : 0);
+	if (gen >= 8) {
+		batch[++i] = offset;
+		batch[++i] = 0;
+	} else if (gen >= 4) {
+		batch[++i] = 0;
+		batch[++i] = offset;
+		reloc.offset += sizeof(uint32_t);
+	} else {
+		batch[i]--;
+		batch[++i] = offset;
+	}
+	batch[++i] = value;
+	batch[++i] = MI_BATCH_BUFFER_END;
+	gem_write(fd, obj[1].handle, 0, batch, sizeof(batch));
+	gem_execbuf(fd, &execbuf);
+	gem_close(fd, obj[1].handle);
+}
+
  static uint32_t
  create_userptr(int fd, uint32_t val, uint32_t *ptr)
  {
@@ -941,6 +996,275 @@ static int test_dmabuf(void)
  	return 0;
  }
+static void test_readonly(int i915)

Hm.. nice interesting and novel fd naming I think. fd, gem_fd I know we have. I wonder if we have drm_fd as well somewhere. Just thinking out loud...

+{
+	unsigned char orig[SHA_DIGEST_LENGTH];
+	uint64_t aperture_size;
+	uint32_t whandle, rhandle;
+	size_t sz, total;
+	void *pages, *space;
+	int memfd;
+
+	/*
+	 * A small batch of pages; small enough to cheaply check for stray
+	 * writes but large enough that we don't create too many VMA pointing
+	 * back to this set from the large arena. The limit on total number
+	 * of VMA for a process is 65,536 (at least on this kernel).
+	 */
+	sz = 16 << 12;

12 for page size, so 16 pages? How it is related to VMA limit from the comment?

+	memfd = memfd_create("pages", 0);
+	igt_require(memfd != -1);

igt_require_fd is available if you care for it...

+	igt_require(ftruncate(memfd, sz) == 0);

..and igt_require_eq, the double sided sword of API growing rich, huh? :)

+
+	pages = mmap(NULL, sz, PROT_WRITE, MAP_SHARED, memfd, 0);
+	igt_assert(pages != MAP_FAILED);
+
+	igt_require(__gem_userptr(i915, pages, sz, true, userptr_flags, &rhandle) == 0);
+	gem_close(i915, rhandle);
+
+	gem_userptr(i915, pages, sz, false, userptr_flags, &whandle);
+
+	total = 2048ull << 20;

Why 2GiB? Express with the VMA limit and sz or just accidentally half of the VMA limit?

+	aperture_size = gem_aperture_size(i915) / 2;
+	if (aperture_size < total)
+		total = aperture_size;
+	total = total / sz * sz;

There is round_down in lib/igt_primes but it would need exporting.

+	igt_info("Using a %'zuB (%'zu pages) arena onto %zu pages\n",
+		 total, total >> 12, sz >> 12);
+
+	/* Create an arena all pointing to the same set of pages */
+	space = mmap(NULL, total, PROT_READ, MAP_ANON | MAP_SHARED, -1, 0);

Allocating address space only?

+	igt_require(space != MAP_FAILED);
+	for (size_t offset = 0; offset < total; offset += sz) {
+		igt_assert(mmap(space + offset, sz,
+				PROT_WRITE, MAP_SHARED | MAP_FIXED,
+				memfd, 0) != MAP_FAILED);
+		*(uint32_t *)(space + offset) = offset;
+	}
+	igt_assert_eq_u32(*(uint32_t *)pages, (uint32_t)(total - sz));

Checking that "arena" somewhat works, ok..

+	igt_assert(mlock(space, total) == 0);
+	close(memfd);
+
+	/* Check we can create a normal userptr bo wrapping the wrapper */
+	gem_userptr(i915, space, total, false, userptr_flags, &rhandle);
+	gem_set_domain(i915, rhandle, I915_GEM_DOMAIN_CPU, 0);
+	for (size_t offset = 0; offset < total; offset += sz)
+		store_dword(i915, rhandle, offset + 4, offset / sz);
+	gem_sync(i915, rhandle);

Do you need to move it back to CPU domain before the asserts?

+	igt_assert_eq_u32(*(uint32_t *)(pages + 0), (uint32_t)(total - sz));
+	igt_assert_eq_u32(*(uint32_t *)(pages + 4), (uint32_t)(total / sz - 1));

Please add a comment somewhere higher up explaining the layout - I got lost what is in the first dword and what in the second of each page, and who writes each.

+	gem_close(i915, rhandle);
+
+	/* Now enforce read-only henceforth */
+	igt_assert(mprotect(space, total, PROT_READ) == 0);

No writes from the CPU, ok, I suppose to guarantee if there is a write where it came from.

Please add a high level comment what the following block will test and how.

+
+	SHA1(pages, sz, orig);
+	igt_fork(child, 1) {
+		const int gen = intel_gen(intel_get_drm_devid(i915));
+		const int nreloc = 1024;

This has a relationship to the size of the batch buffer created lower below?

+		struct drm_i915_gem_relocation_entry *reloc;
+		struct drm_i915_gem_exec_object2 obj[2];
+		struct drm_i915_gem_execbuffer2 exec;
+		unsigned char ref[SHA_DIGEST_LENGTH], result[SHA_DIGEST_LENGTH];
+		uint32_t *batch;
+		int i;
+
+		reloc = calloc(sizeof(*reloc), nreloc);
+		gem_userptr(i915, space, total, true, userptr_flags, &rhandle);
+
+

Extra newline.

+		memset(obj, 0, sizeof(obj));
+		obj[0].flags = LOCAL_EXEC_OBJECT_SUPPORTS_48B;
+		obj[1].handle = gem_create(i915, 4096*16);

This is the size of store dw times times nreloc? Relationships need to be clearer and expressed in one place.

+		obj[1].relocation_count = nreloc;
+		obj[1].relocs_ptr = to_user_pointer(reloc);
+
+		batch = gem_mmap__wc(i915, obj[1].handle, 0, 4096*16, PROT_WRITE);
+
+		memset(&exec, 0, sizeof(exec));
+		exec.buffer_count =2;
+		exec.buffers_ptr = to_user_pointer(obj);
+
+		for_each_engine(i915, exec.flags) {
+			/* First tweak the backing store through the write */
+			i = 0;
+			obj[0].handle = whandle;
+			for (int n = 0; n < nreloc; n++) {
+				uint64_t offset;
+
+				reloc[n].target_handle = obj[0].handle;
+				reloc[n].delta = 4*(rand() % (sz/4));
+				reloc[n].offset = (i+1) * sizeof(uint32_t);

You can add spaces around operators to follow our coding style since space is not constrained here.

+				reloc[n].presumed_offset = obj[0].offset;
+				reloc[n].read_domains = I915_GEM_DOMAIN_RENDER;
+				reloc[n].write_domain = I915_GEM_DOMAIN_RENDER;
+
+				offset = reloc[n].presumed_offset + reloc[n].delta;
+
+				batch[i] = MI_STORE_DWORD_IMM | (gen < 6 ? 1 << 22 : 0);
+				if (gen >= 8) {
+					batch[++i] = offset;
+					batch[++i] = offset >> 32;
+				} else if (gen >= 4) {
+					batch[++i] = 0;
+					batch[++i] = offset;
+					reloc[n].offset += sizeof(uint32_t);
+				} else {
+					batch[i]--;
+					batch[++i] = offset;
+				}
+				batch[++i] = rand();
+				i++;
+			}
+			batch[i] = MI_BATCH_BUFFER_END;

Somehow make this possible via previously added store_dword helper instead of duplicating?

+
+			gem_execbuf(i915, &exec);
+			gem_sync(i915, obj[0].handle);
+			SHA1(pages, sz, ref);
+
+			igt_assert(memcmp(ref, orig, sizeof(ref)));
+			memcpy(orig, ref, sizeof(orig));
+
+			/* Now try the same through the read-only handle */
+			i = 0;
+			obj[0].handle = rhandle;
+			for (int n = 0; n < nreloc; n++) {
+				uint64_t offset;
+
+				reloc[n].target_handle = obj[0].handle;
+				reloc[n].delta = 4*(rand() % (total/4));
+				reloc[n].offset = (i+1) * sizeof(uint32_t);
+				reloc[n].presumed_offset = obj[0].offset;
+				reloc[n].read_domains = I915_GEM_DOMAIN_RENDER;
+				reloc[n].write_domain = I915_GEM_DOMAIN_RENDER;
+
+				offset = reloc[n].presumed_offset + reloc[n].delta;
+
+				batch[i] = MI_STORE_DWORD_IMM | (gen < 6 ? 1 << 22 : 0);
+				if (gen >= 8) {
+					batch[++i] = offset;
+					batch[++i] = offset >> 32;
+				} else if (gen >= 4) {
+					batch[++i] = 0;
+					batch[++i] = offset;
+					reloc[n].offset += sizeof(uint32_t);
+				} else {
+					batch[i]--;
+					batch[++i] = offset;
+				}
+				batch[++i] = rand();
+				i++;
+			}
+			batch[i] = MI_BATCH_BUFFER_END;

Am I seeing a copy-pasted loop? You know what's next! :D

+
+			gem_execbuf(i915, &exec);
+			gem_sync(i915, obj[0].handle);
+			SHA1(pages, sz, result);
+
+			/*
+			 * As the writes into the read-only GPU bo should fail,
+			 * the SHA1 hash of the backing store should be
+			 * unaffected.
+			 */
+			igt_assert(memcmp(ref, result, SHA_DIGEST_LENGTH) == 0);
+		}
+
+		munmap(batch, 16*4096);
+		gem_close(i915, obj[1].handle);
+		gem_close(i915, rhandle);
+	}
+	igt_waitchildren();
+
+	munmap(space, total);
+	munmap(pages, sz);
+}

Okay more or less. Just want some tweaks and high level description since I (or anyone in the future) don't need/want to reverse engineer the patterns.

+
+static jmp_buf sigjmp;
+static void sigjmp_handler(int sig)
+{
+	siglongjmp(sigjmp, sig);
+}
+
+static void test_readonly_mmap(int i915)
+{

Please add high level test description since there is some trickery below.

+	unsigned char original[SHA_DIGEST_LENGTH];
+	unsigned char result[SHA_DIGEST_LENGTH];
+	uint32_t handle;
+	uint32_t sz;
+	void *pages;
+	void *ptr;
+	int sig;
+
+	igt_require(igt_setup_clflush());
+
+	sz = 16 << 12;
+	pages = mmap(NULL, sz, PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
+	igt_assert(pages != MAP_FAILED);
+
+	igt_require(__gem_userptr(i915, pages, sz, true, userptr_flags, &handle) == 0);
+	gem_set_caching(i915, handle, 0);
+
+	memset(pages, 0xa5, sz);
+	igt_clflush_range(pages, sz);

Why are cache flushed needed in this test? Because they cannot be done via domain management?

+	SHA1(pages, sz, original);
+
+	ptr = __gem_mmap__gtt(i915, handle, sz, PROT_WRITE);
+	igt_assert(ptr == NULL);
+
+	ptr = gem_mmap__gtt(i915, handle, sz, PROT_READ);
+	gem_close(i915, handle);
+
+	if (!(sig = sigsetjmp(sigjmp, 1))) {

What does this do? Comment?

+		signal(SIGBUS, sigjmp_handler);
+		signal(SIGSEGV, sigjmp_handler);
+		memset(ptr, 0x5a, sz);
+		igt_assert(0);
+	}
+	igt_assert_eq(sig, SIGSEGV);
+
+	igt_assert(mprotect(ptr, sz, PROT_WRITE));

Why is this needed?

+	munmap(ptr, sz);
+
+	igt_clflush_range(pages, sz);
+	SHA1(pages, sz, result);
+	igt_assert(!memcmp(original, result, sizeof(original)));
+
+	munmap(pages, sz);
+}
+
+static void test_readonly_pwrite(int i915)
+{
+	unsigned char original[SHA_DIGEST_LENGTH];
+	unsigned char result[SHA_DIGEST_LENGTH];
+	uint32_t handle;
+	uint32_t sz;
+	void *pages;
+
+	igt_require(igt_setup_clflush());
+
+	sz = 16 << 12;
+	pages = mmap(NULL, sz, PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
+	igt_assert(pages != MAP_FAILED);
+
+	igt_require(__gem_userptr(i915, pages, sz, true, userptr_flags, &handle) == 0);
+	memset(pages, 0xa5, sz);
+	SHA1(pages, sz, original);
+
+	for (int page = 0; page < 16; page++) {
+		char data[4096];
+
+		memset(data, page, sizeof(data));
+		igt_assert_eq(__gem_write(i915, handle, page << 12, data, sizeof(data)), -EINVAL);
+	}
+
+	gem_close(i915, handle);
+
+	SHA1(pages, sz, result);
+	igt_assert(!memcmp(original, result, sizeof(original)));
+
+	munmap(pages, sz);
+}
+
  static int test_usage_restrictions(int fd)
  {
  	void *ptr;
@@ -961,10 +1285,6 @@ static int test_usage_restrictions(int fd)
  	ret = __gem_userptr(fd, (char *)ptr + 1, PAGE_SIZE - 1, 0, userptr_flags, &handle);
  	igt_assert_neq(ret, 0);
- /* Read-only not supported. */
-	ret = __gem_userptr(fd, (char *)ptr, PAGE_SIZE, 1, userptr_flags, &handle);
-	igt_assert_neq(ret, 0);
-
  	free(ptr);
return 0;
@@ -1502,6 +1822,15 @@ int main(int argc, char **argv)
  		igt_subtest("dmabuf-unsync")
  			test_dmabuf();
+ igt_subtest("readonly-unsync")
+			test_readonly(fd);
+
+		igt_subtest("readonly-mmap-unsync")
+			test_readonly_mmap(fd);
+
+		igt_subtest("readonly-pwrite-unsync")
+			test_readonly_pwrite(fd);
+
  		for (unsigned flags = 0; flags < ALL_FORKING_EVICTIONS + 1; flags++) {
  			igt_subtest_f("forked-unsync%s%s%s-%s",
  					flags & FORKING_EVICTIONS_SWAPPING ? "-swapping" : "",


Looks like thorough coverage, just some final polish needed.

Regards,

Tvrtko
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx




[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux