[igt-dev] [PATCH i-g-t 3/3] tests/i915/gem_mmap_offset: Add new API test for gem_mmap_offset

[Chris Wilson]

Quoting Vanshidhar Konda (2019-11-25 17:32:10)
> On Mon, Nov 25, 2019 at 10:23:09AM +0000, Chris Wilson wrote:
> >Quoting Zbigniew Kempczyński (2019-11-25 10:09:57)
> >> From: Lukasz Kalamarz <lukasz.kalamarz at intel.com>
> >>
> >> Few simple tests which tries to create / mmap buffer objects
> >> using GEM_MMAP_OFFSET uAPI.
> >>
> >> Signed-off-by: Lukasz Kalamarz <lukasz.kalamarz at intel.com>
> >> Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> >> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> >> Cc: Vanshidhar Konda <vanshidhar.r.konda at intel.com>
> >> ---
> >>  tests/Makefile.sources       |   3 +
> >>  tests/i915/gem_mmap_offset.c | 127 +++++++++++++++++++++++++++++++++++
> >>  tests/meson.build            |   1 +
> >>  3 files changed, 131 insertions(+)
> >>  create mode 100644 tests/i915/gem_mmap_offset.c
> >>
> >> diff --git a/tests/Makefile.sources b/tests/Makefile.sources
> >> index 27801c89..9c6c3933 100644
> >> --- a/tests/Makefile.sources
> >> +++ b/tests/Makefile.sources
> >> @@ -320,6 +320,9 @@ gem_mmap_SOURCES = i915/gem_mmap.c
> >>  TESTS_progs += gem_mmap_gtt
> >>  gem_mmap_gtt_SOURCES = i915/gem_mmap_gtt.c
> >>
> >> +TESTS_progs += gem_mmap_offset
> >> +gem_mmap_offset_SOURCES = i915/gem_mmap_offset.c
> >> +
> >>  TESTS_progs += gem_mmap_offset_exhaustion
> >>  gem_mmap_offset_exhaustion_SOURCES = i915/gem_mmap_offset_exhaustion.c
> >>
> >> diff --git a/tests/i915/gem_mmap_offset.c b/tests/i915/gem_mmap_offset.c
> >> new file mode 100644
> >> index 00000000..44dca831
> >> --- /dev/null
> >> +++ b/tests/i915/gem_mmap_offset.c
> >> @@ -0,0 +1,127 @@
> >> +/*
> >> + * Copyright © 2019 Intel Corporation
> >> + *
> >> + * Permission is hereby granted, free of charge, to any person obtaining a
> >> + * copy of this software and associated documentation files (the "Software"),
> >> + * to deal in the Software without restriction, including without limitation
> >> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> >> + * and/or sell copies of the Software, and to permit persons to whom the
> >> + * Software is furnished to do so, subject to the following conditions:
> >> + *
> >> + * The above copyright notice and this permission notice (including the next
> >> + * paragraph) shall be included in all copies or substantial portions of the
> >> + * Software.
> >> + *
> >> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> >> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> >> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> >> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> >> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> >> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> >> + * IN THE SOFTWARE.
> >> + */
> >> +
> >> +#include "igt.h"
> >> +#include <errno.h>
> >> +#include <sys/stat.h>
> >> +#include <sys/ioctl.h>
> >> +#include "drm.h"
> >> +
> >> +IGT_TEST_DESCRIPTION("Basic MMAP_OFFSET IOCTL tests for mem regions\n");
> >> +
> >> +static int mmap_offset_ioctl(int fd, struct local_i915_gem_mmap_offset *arg)
> >> +{
> >> +       int err = 0;
> >> +
> >> +       if (igt_ioctl(fd, LOCAL_IOCTL_I915_GEM_MMAP_OFFSET, arg))
> >> +               err = -errno;
> >> +
> >> +       errno = 0;
> >> +       return err;
> >> +}
> >> +
> >> +static void mmap_offset_bad_object(int fd)
> >> +{
> >> +       uint32_t real_handle;
> >> +       uint32_t handles[20];
> >> +       int i = 0;
> >> +
> >> +       real_handle = gem_create(fd, 4096);
> >> +
> >> +       handles[i++] = 0xdeadbeef;
> >> +       for (int bit = 0; bit < 16; bit++)
> >> +               handles[i++] = real_handle | (1 << (bit + 16));
> >> +       handles[i] = real_handle + 1;
> >> +
> >> +       for (; i >= 0; i--) {
> >> +               struct local_i915_gem_mmap_offset arg = {
> >> +                       .handle = handles[i],
> >> +                       .flags = LOCAL_I915_MMAP_OFFSET_WC,
> >
> >Hmm, WC isn't guaranteed on all platforms, neither is GTT, nor may be
> >WB, nor UC.
> >
> >That's quite a conundrum. I would actually say use OFFSET_WB for basic
> >API correctness checks as that covers all platforms we have today, and
> >we'll cross that bridge when we come to it.
> 
> Would doing UC not work across all platforms we have? Since, this code
> path should not really be performance sensitive, I thought UC would have
> been the safest fall back option.

No, UC also depends on PAT which not all platforms support.
-Chris