[PATCH i-g-t] xe: Add test to check pci memory barrier capability

[Upadhyay, Tejas]

> -----Original Message-----
> From: Kamil Konieczny <kamil.konieczny at linux.intel.com>
> Sent: Wednesday, October 9, 2024 4:06 PM
> To: igt-dev at lists.freedesktop.org
> Cc: Upadhyay, Tejas <tejas.upadhyay at intel.com>; intel-
> gfx at lists.freedesktop.org
> Subject: Re: [PATCH i-g-t] xe: Add test to check pci memory barrier capability
> 
> Hi Tejas,
> On 2024-10-09 at 15:26:08 +0530, 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>
> > ---
> >  include/drm-uapi/xe_drm.h       |  3 ++
> 
> Please send updates to drm-uapi with a separate patch.

Sure, will do that.

Tejas
> 
> Regards,
> Kamil
> 
> >  tests/intel/xe_pci_membarrier.c | 77
> +++++++++++++++++++++++++++++++++
> >  tests/meson.build               |  1 +
> >  3 files changed, 81 insertions(+)
> >  create mode 100644 tests/intel/xe_pci_membarrier.c
> >
> > diff --git a/include/drm-uapi/xe_drm.h b/include/drm-uapi/xe_drm.h
> > index f0a450db9..866dc8060 100644
> > --- a/include/drm-uapi/xe_drm.h
> > +++ b/include/drm-uapi/xe_drm.h
> > @@ -823,6 +823,9 @@ struct drm_xe_gem_mmap_offset {
> >  	/** @offset: The fake offset to use for subsequent mmap call */
> >  	__u64 offset;
> >
> > +	/* Specific MMAP offset for PCI memory barrier */ #define
> > +DRM_XE_PCI_BARRIER_MMAP_OFFSET (0x50 << PAGE_SHIFT)
> > +
> >  	/** @reserved: Reserved */
> >  	__u64 reserved[2];
> >  };
> > diff --git a/tests/intel/xe_pci_membarrier.c
> > b/tests/intel/xe_pci_membarrier.c new file mode 100644 index
> > 000000000..a28a01d4b
> > --- /dev/null
> > +++ b/tests/intel/xe_pci_membarrier.c
> > @@ -0,0 +1,77 @@
> > +// 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: pci-membarrier-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;
> > +	uint64_t offset = DRM_XE_PCI_BARRIER_MMAP_OFFSET;
> > +	unsigned int prot = PROT_WRITE;
> > +	uint32_t *ptr;
> > +	uint64_t size = PAGE_SIZE;
> > +	struct timespec tv;
> > +
> > +	ptr = mmap(NULL, size, prot, flags, xe, offset);
> > +	igt_assert(ptr != MAP_FAILED);
> > +
> > +	/* 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) {
> > +			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("pci-membarrier-basic")
> > +		pci_membarrier(xe);
> > +
> > +	igt_fixture {
> > +		close(xe);
> > +	}
> > +}
> > diff --git a/tests/meson.build b/tests/meson.build index
> > e5d8852f3..310ef0e0d 100644
> > --- a/tests/meson.build
> > +++ b/tests/meson.build
> > @@ -304,6 +304,7 @@ intel_xe_progs = [
> >  	'xe_noexec_ping_pong',
> >  	'xe_oa',
> >  	'xe_pat',
> > +        'xe_pci_membarrier',
> >  	'xe_peer2peer',
> >  	'xe_pm',
> >  	'xe_pm_residency',
> > --
> > 2.34.1
> >