[PATCH i-g-t V2 2/2] tests/intel: Add xe_pci_membarrier test

[Upadhyay, Tejas]

> -----Original Message-----
> From: Auld, Matthew <matthew.auld at intel.com>
> Sent: Friday, November 1, 2024 7:25 PM
> To: Upadhyay, Tejas <tejas.upadhyay at intel.com>; igt-
> dev at lists.freedesktop.org; intel-xe at lists.freedesktop.org
> Subject: Re: [PATCH i-g-t V2 2/2] tests/intel: Add xe_pci_membarrier test
> 
> On 23/10/2024 10:43, Tejas Upadhyay wrote:
> > We want to make sure that direct mmap mapping of physical page at
> > doorbell space and whole page is accessible in order to use pci memory
> > barrier effect effectively.
> >
> > This is basic pci memory barrier test to showcase xe driver support
> > for feature. In follow up patches we will have more of corner and
> > negative tests added later.
> >
> > Signed-off-by: Tejas Upadhyay <tejas.upadhyay at intel.com>
> > ---
> >   tests/intel/xe_pci_membarrier.c | 80
> > +++++++++++++++++++++++++++++++++
> 
> Could probably just plonk this in the existing mmap offset tests file?

I tried this, but looks like none of existing methods which are using bo-create looks related to this test. Also negative tests are also going to be different for this test. I would think it should be good to keep this test separate. What you think!

Tejas

> 
> >   tests/meson.build               |  1 +
> >   2 files changed, 81 insertions(+)
> >   create mode 100644 tests/intel/xe_pci_membarrier.c
> >
> > diff --git a/tests/intel/xe_pci_membarrier.c
> > b/tests/intel/xe_pci_membarrier.c new file mode 100644 index
> > 000000000..d0bf447b6
> > --- /dev/null
> > +++ b/tests/intel/xe_pci_membarrier.c
> > @@ -0,0 +1,80 @@
> > +// SPDX-License-Identifier: MIT
> > +/*
> > + * Copyright(c) 2024 Intel Corporation. All rights reserved.
> > + */
> > +
> > +#include "xe_drm.h"
> > +#include "igt.h"
> > +
> > +/**
> > + * TEST: Test if the driver is capable of putting pci memory barrier
> > +using mmap
> > + * Category: Core
> > + * Mega feature: General Core features
> > + * Sub-category: Memory management tests
> > + * Functionality: mmap with pre-defined offset  */
> > +
> > +IGT_TEST_DESCRIPTION("Basic MMAP tests pci memory barrier effect with
> > +special offset"); #define PAGE_SHIFT 12 #define PAGE_SIZE 4096
> > +
> > +/**
> > + * SUBTEST: basic
> > + * Description: create pci memory barrier with write on defined mmap
> offset.
> > + * Test category: functionality test
> > + *
> > + */
> > +
> > +static void pci_membarrier(int xe)
> > +{
> > +	uint64_t flags = MAP_SHARED;
> > +	unsigned int prot = PROT_WRITE;
> > +	uint32_t *ptr;
> > +	uint64_t size = PAGE_SIZE;
> > +	struct timespec tv;
> > +        struct drm_xe_gem_mmap_offset mmo = {
> > +                .handle = 0,
> > +                .flags = DRM_XE_MMAP_OFFSET_FLAG_PCI_BARRIER,
> > +        };
> > +
> > +        igt_assert_eq(igt_ioctl(xe, DRM_IOCTL_XE_GEM_MMAP_OFFSET,
> &mmo), 0);
> > +        ptr = mmap(NULL, size, prot, flags, xe, mmo.offset);
> > +	igt_assert(ptr != MAP_FAILED);
> 
> nit: formatting
> 
> > +
> > +	/* Check whole page for any errors, also check as
> > +	 * we should not read written values back
> > +	 */
> > +	for (int i = 0; i < size / sizeof(*ptr); i++) {
> > +		/* It is expected unconfigured doorbell space
> > +		 * will return read value 0xdeadbeef
> > +		 */
> > +		igt_assert_eq_u32(READ_ONCE(ptr[i]), 0xdeadbeef);
> > +
> > +		igt_gettime(&tv);
> > +		ptr[i] = i;
> > +		if (READ_ONCE(ptr[i]) == i) {
> 
> Can this actually happen where the value is written?
> 
> I think also consider adding some negative testcases. For example:
> 
> - Try to mmap something larger than 4K. Ensure we get an error.
> - Try BARRIER mmap_offset, and also supply a BO. Ensure we get an error.
> 
> > +			while (READ_ONCE(ptr[i]) == i)
> > +				;
> > +			igt_info("fd:%d value retained for %"PRId64"ns
> pos:%d\n",
> > +				 xe, igt_nsec_elapsed(&tv), i);
> > +		}
> > +		igt_assert_neq(READ_ONCE(ptr[i]), i);
> > +	}
> > +
> > +	munmap(ptr, size);
> > +}
> > +
> > +igt_main
> > +{
> > +	int xe;
> > +
> > +	igt_fixture {
> > +		xe = drm_open_driver(DRIVER_XE);
> > +	}
> > +
> > +	igt_subtest_f("basic")
> > +		pci_membarrier(xe);
> > +
> > +	igt_fixture
> > +		drm_close_driver(xe);
> > +}
> > diff --git a/tests/meson.build b/tests/meson.build index
> > 34b87b125..15131d812 100644
> > --- a/tests/meson.build
> > +++ b/tests/meson.build
> > @@ -306,6 +306,7 @@ intel_xe_progs = [
> >   	'xe_noexec_ping_pong',
> >   	'xe_oa',
> >   	'xe_pat',
> > +        'xe_pci_membarrier',
> >   	'xe_peer2peer',
> >   	'xe_pm',
> >   	'xe_pm_residency',