Re: [PATCH i-g-t v2 2/4] tests/intel/xe_madvise: Add atomic-device subtest

["Sharma, Nishit" <nishit.sharma@intel.com>]

On 5/11/2026 9:22 AM, Varun Gupta wrote:
> Validate that madvise ATOMIC_DEVICE allows GPU MI_ATOMIC_INC on SVM
> memory.  The test creates a fault-mode VM with CPU_ADDR_MIRROR binding
> over heap memory allocated via aligned_alloc().  After setting
> ATOMIC_DEVICE via DRM_XE_MEM_RANGE_ATTR_ATOMIC madvise, the GPU
> executes MI_ATOMIC_INC through the page-fault handler which migrates
> pages to VRAM for device atomics.
>
> Also adds the shared atomic test infrastructure: struct
> atomic_data, atomic_build_batch() helper, timeout constants, and the
> atomic subtest group gated on VRAM and fault-mode support.
>
> Signed-off-by: Varun Gupta <varun.gupta@intel.com>
>
> v2: Add UNMAP of CPU_ADDR_MIRROR binding before xe_vm_destroy.
>      Add pagefault count print before/after exec (Nishit).
> ---
>   tests/intel/xe_madvise.c | 122 ++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 121 insertions(+), 1 deletion(-)
>
> diff --git a/tests/intel/xe_madvise.c b/tests/intel/xe_madvise.c
> index e79cafbff..f343f3c8c 100644
> --- a/tests/intel/xe_madvise.c
> +++ b/tests/intel/xe_madvise.c
> @@ -14,9 +14,12 @@
>   #include "igt.h"
>   #include "xe_drm.h"
>   
> +#include "intel_gpu_commands.h"
> +#include "lib/igt_syncobj.h"
> +#include "lib/intel_reg.h"
> +#include "xe/xe_gt.h"
>   #include "xe/xe_ioctl.h"
>   #include "xe/xe_query.h"
> -#include "lib/igt_syncobj.h"
>   
>   /* Purgeable test constants */
>   #define PURGEABLE_ADDR		0x1a0000
> @@ -27,6 +30,11 @@
>   #define PURGEABLE_TEST_PATTERN	0xc0ffee
>   #define PURGEABLE_DEAD_PATTERN	0xdead
>   
> +/* Atomic test constants */
> +#define USER_FENCE_VALUE	0xdeadbeefdeadbeefull
> +#define FIVE_SEC		(5LL * NSEC_PER_SEC)
> +#define QUARTER_SEC		(NSEC_PER_SEC / 4)
> +
>   static bool xe_has_purgeable_support(int fd)
>   {
>   	struct drm_xe_query_config *config = xe_config(fd);
> @@ -768,6 +776,107 @@ out:
>   		igt_skip("Unable to induce purge on this platform/config");
>   }
>   
> +/*
> + * Atomic madvise subtests — validate DRM_XE_MEM_RANGE_ATTR_ATOMIC
> + * modes (DEVICE, GLOBAL, CPU) on fault-mode SVM VMAs.
> + */
> +
> +struct atomic_data {
> +	uint32_t batch[32];
> +	uint64_t vm_sync;
> +	uint64_t exec_sync;
> +	uint32_t data;
> +};
> +
> +static void atomic_build_batch(struct atomic_data *d, uint64_t gpu_addr)
> +{
> +	uint64_t data_offset = (char *)&d->data - (char *)d;
> +	uint64_t sdi_addr = gpu_addr + data_offset;
> +	int b = 0;
> +
> +	d->batch[b++] = MI_ATOMIC | MI_ATOMIC_INC;
> +	d->batch[b++] = sdi_addr;
> +	d->batch[b++] = sdi_addr >> 32;
> +	d->batch[b++] = MI_BATCH_BUFFER_END;
> +	igt_assert(b <= ARRAY_SIZE(d->batch));
> +}
> +
> +/**
> + * SUBTEST: atomic-device
> + * Description: madvise atomic device supports only GPU atomic operations,
> + *		test executes GPU MI_ATOMIC_INC on SVM memory via fault handler
> + * Test category: functionality test
> + */
> +static void test_atomic_device(int fd, struct drm_xe_engine_class_instance *eci)
> +{
> +	struct drm_xe_sync sync[1] = {
> +		{ .type = DRM_XE_SYNC_TYPE_USER_FENCE,
> +		  .flags = DRM_XE_SYNC_FLAG_SIGNAL,
> +		  .timeline_value = USER_FENCE_VALUE },
> +	};
> +	struct drm_xe_exec exec = {
> +		.num_batch_buffer = 1,
> +		.num_syncs = 1,
> +		.syncs = to_user_pointer(sync),
> +	};
> +	struct atomic_data *data;
> +	uint32_t vm, exec_queue;
> +	uint64_t addr;
> +	size_t bo_size;
> +	int va_bits;
> +	int pf_count_before, pf_count_after;
> +
> +	va_bits = xe_va_bits(fd);
> +	vm = xe_vm_create(fd, DRM_XE_VM_CREATE_FLAG_LR_MODE |
> +			  DRM_XE_VM_CREATE_FLAG_FAULT_MODE, 0);
> +
> +	bo_size = xe_bb_size(fd, sizeof(*data));
> +	data = aligned_alloc(bo_size, bo_size);
> +	igt_assert(data);
> +	memset(data, 0, bo_size);
> +
> +	addr = to_user_pointer(data);
> +
> +	/* Bind entire VA space as CPU_ADDR_MIRROR */
> +	sync[0].addr = to_user_pointer(&data->vm_sync);
> +	__xe_vm_bind_assert(fd, vm, 0, 0, 0, 0, 0x1ull << va_bits,
> +			    DRM_XE_VM_BIND_OP_MAP,
> +			    DRM_XE_VM_BIND_FLAG_CPU_ADDR_MIRROR,
> +			    sync, 1, 0, 0);
> +	xe_wait_ufence(fd, &data->vm_sync, USER_FENCE_VALUE, 0, FIVE_SEC);
> +	data->vm_sync = 0;
> +
> +	xe_vm_madvise(fd, vm, addr, bo_size, 0,
> +		      DRM_XE_MEM_RANGE_ATTR_ATOMIC, DRM_XE_ATOMIC_DEVICE, 0, 0);
> +
> +	atomic_build_batch(data, addr);
> +
> +	exec_queue = xe_exec_queue_create(fd, vm, eci, 0);
> +	exec.exec_queue_id = exec_queue;
> +	exec.address = addr + ((char *)&data->batch - (char *)data);
> +
> +	pf_count_before = xe_gt_stats_get_count(fd, eci->gt_id,
> +					"svm_pagefault_count");
> +
> +	sync[0].addr = to_user_pointer(&data->exec_sync);
> +	xe_exec(fd, &exec);
> +	xe_wait_ufence(fd, &data->exec_sync, USER_FENCE_VALUE,
> +		       exec_queue, FIVE_SEC);
> +
> +	pf_count_after = xe_gt_stats_get_count(fd, eci->gt_id,
> +					       "svm_pagefault_count");
> +	igt_info("Pagefault count: before=%d, after=%d\n",
> +		 pf_count_before, pf_count_after);

small nit: this will print pf count all the times whether pf not 
generated . Add loop

if (pf_count_before != pf_count_after)

igt_info("pf count prints);

> +
> +	igt_assert_eq(data->data, 1);
> +
> +	xe_exec_queue_destroy(fd, exec_queue);
> +	__xe_vm_bind_assert(fd, vm, 0, 0, 0, 0, 0x1ull << va_bits,
> +			    DRM_XE_VM_BIND_OP_UNMAP, 0, NULL, 0, 0, 0);
> +	free(data);
> +	xe_vm_destroy(fd, vm);
> +}
> +
>   int igt_main()
>   {
>   	struct drm_xe_engine_class_instance *hwe;
> @@ -826,6 +935,17 @@ int igt_main()
>   			}
>   	}
>   
> +	igt_subtest_group() {
> +		igt_fixture() {
> +			igt_require(xe_has_vram(fd));
> +			igt_require(!xe_supports_faults(fd));
> +		}
> +
> +		igt_subtest("atomic-device")
> +			xe_for_each_engine(fd, hwe)
> +				test_atomic_device(fd, hwe);
> +	}
> +
>   	igt_fixture() {
>   		xe_device_put(fd);
>   		drm_close_driver(fd);

With above change LGTM:

Reviewed-by: Nishit Sharma <nishit.sharma@intel.com>