RE: [PATCH i-g-t v3 3/8] tests/intel/xe_madvise: Add dontneed-before-mmap subtest

Gurram, Pravalika
2026-02-23T05:09:40Z

> -----Original Message-----
> From: Yadav, Arvind <arvind.yadav@intel.com>
> Sent: Tuesday, 17 February, 2026 08:04 AM
> To: igt-dev@lists.freedesktop.org
> Cc: Brost, Matthew <matthew.brost@intel.com>; Ghimiray, Himal Prasad
> <himal.prasad.ghimiray@intel.com>; thomas.hellstrom@linux.intel.com;
> Sharma, Nishit <nishit.sharma@intel.com>; Gurram, Pravalika
> <pravalika.gurram@intel.com>
> Subject: [PATCH i-g-t v3 3/8] tests/intel/xe_madvise: Add dontneed-before-
> mmap subtest
>
> This test validates kernel behavior when mapping a BO that was already
> marked as purgeable and purged before mmap. After purging the BO under
> memory pressure, the test attempts to mmap and access it. The kernel should
> trigger SIGBUS or SIGSEGV when accessing the purged mapping, confirming
> that purged memory is properly invalidated.
>
> Cc: Nishit Sharma <nishit.sharma@intel.com>
> Cc: Pravalika Gurram <pravalika.gurram@intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
> Signed-off-by: Arvind Yadav <arvind.yadav@intel.com>
> ---
> tests/intel/xe_madvise.c | 219
> +++++++++++++++++++++++++++++++++++++++
> tests/meson.build | 1 +
> 2 files changed, 220 insertions(+)
> create mode 100644 tests/intel/xe_madvise.c
>
> diff --git a/tests/intel/xe_madvise.c b/tests/intel/xe_madvise.c new file mode
> 100644 index 000000000..7dbe70f42
> --- /dev/null
> +++ b/tests/intel/xe_madvise.c
> @@ -0,0 +1,219 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2025 Intel Corporation
> + */
> +
> +/**
> + * TEST: Validate purgeable BO madvise functionality
> + * Category: Core
> + * Mega feature: General Core features
> + * Sub-category: Memory management tests
> + * Functionality: madvise, purgeable
> + */
> +
> +#include "igt.h"
> +#include "xe_drm.h"
> +
> +#include "xe/xe_ioctl.h"
> +#include "xe/xe_query.h"
> +
> +/* Purgeable test constants */
> +#define PURGEABLE_ADDR 0x1a0000
> +#define PURGEABLE_BO_SIZE 4096
> +
> +/**
> + * trigger_memory_pressure - Fill VRAM + 25% to force purgeable reclaim
> + * @fd: DRM file descriptor
> + * @vm: VM handle (unused, kept for API compatibility)
> + *
> + * Allocates BOs in a temporary VM until VRAM is overcommitted,
> + * forcing the kernel to purge DONTNEED-marked BOs.
> + */
> +static void trigger_memory_pressure(int fd, uint32_t vm) {
> + uint64_t vram_size, overpressure;
> + const uint64_t chunk = 8ull << 20; /* 8 MiB */
> + int max_objs, n = 0;
> + uint32_t *handles;
> + uint64_t total;
> + void *p;
> + uint32_t handle, temp_vm;
> +
> + /* Use a separate VM so pressure BOs don't affect the test VM */
> + temp_vm = xe_vm_create(fd, 0, 0);
> +
> + vram_size = xe_visible_vram_size(fd, 0);
> + /* Scale overpressure to 25% of VRAM, minimum 64MB */
> + overpressure = vram_size / 4;
> + if (overpressure < (64 << 20))
> + overpressure = 64 << 20;
> +
> + max_objs = (vram_size + overpressure) / chunk + 1;
> + handles = malloc(max_objs * sizeof(*handles));
> + igt_assert(handles);
> +
> + total = 0;
> + while (total < vram_size + overpressure && n < max_objs) {
> + handle = xe_bo_create(fd, temp_vm, chunk,
> + vram_if_possible(fd, 0),
> +
> DRM_XE_GEM_CREATE_FLAG_NEEDS_VISIBLE_VRAM);
> + handles[n++] = handle;
> + total += chunk;
> +
> + p = xe_bo_map(fd, handle, chunk);
> + igt_assert(p != MAP_FAILED);
> +
> + /* Fault in all pages so they actually consume VRAM */
> + memset(p, 0xCD, chunk);
> + munmap(p, chunk);
> + }
> +
> + /* Allow shrinker time to process pressure */
> + usleep(100000);
> +
> + for (int i = 0; i < n; i++)
> + gem_close(fd, handles[i]);
> +
> + free(handles);
> +
> + xe_vm_destroy(fd, temp_vm);
> +}
> +
> +static jmp_buf jmp;
> +
> +__noreturn static void sigtrap(int sig) {
> + siglongjmp(jmp, sig);
> +}
> +
> +/**
> + * purgeable_mark_and_verify_purged - Mark DONTNEED, pressure, check
> +purged
> + * @fd: DRM file descriptor
> + * @vm: VM handle
> + * @addr: Virtual address of the BO
> + * @size: Size of the BO
> + *
> + * Returns true if the BO was purged under memory pressure.
> + */
> +static bool purgeable_mark_and_verify_purged(int fd, uint32_t vm,
> +uint64_t addr, size_t size) {
> + uint32_t retained;
> +
> + /* Mark as DONTNEED */
> + retained = xe_vm_madvise_purgeable(fd, vm, addr, size,
> +
> DRM_XE_VMA_PURGEABLE_STATE_DONTNEED);
> + if (retained != 1)
> + return false;
> +
> + /* Trigger memory pressure */
> + trigger_memory_pressure(fd, vm);
> +
> + /* Verify purged */
> + retained = xe_vm_madvise_purgeable(fd, vm, addr, size,
> +
> DRM_XE_VMA_PURGEABLE_STATE_WILLNEED);
> + return retained == 0;
> +}
> +
> +/**
> + * purgeable_setup_simple_bo - Setup VM and bind a single BO
> + * @fd: DRM file descriptor
> + * @vm: Output VM handle
> + * @bo: Output BO handle
> + * @addr: Virtual address to bind at
> + * @size: Size of the BO
> + * @use_scratch: Whether to use scratch page flag
> + *
> + * Helper to create VM, BO, and bind it at the specified address.
> + */
> +static void purgeable_setup_simple_bo(int fd, uint32_t *vm, uint32_t *bo,
> + uint64_t addr, size_t size, bool
> use_scratch) {
> + struct drm_xe_sync sync = {
> + .type = DRM_XE_SYNC_TYPE_USER_FENCE,
> + .flags = DRM_XE_SYNC_FLAG_SIGNAL,
> + .timeline_value = 1,
> + };
> + uint64_t sync_val = 0;
> +
> + *vm = xe_vm_create(fd, use_scratch ?
> DRM_XE_VM_CREATE_FLAG_SCRATCH_PAGE : 0, 0);
> + *bo = xe_bo_create(fd, *vm, size, vram_if_possible(fd, 0),
> +
> DRM_XE_GEM_CREATE_FLAG_NEEDS_VISIBLE_VRAM);
> +
> + sync.addr = to_user_pointer(&sync_val);
> + xe_vm_bind_async(fd, *vm, 0, *bo, 0, addr, size, &sync, 1);
> + xe_wait_ufence(fd, &sync_val, 1, 0, NSEC_PER_SEC); }
> +
> +/**
> + * SUBTEST: dontneed-before-mmap
> + * Description: Mark BO as DONTNEED before mmap, verify mmap fails or
> +SIGBUS on access
> + * Test category: functionality test
> + */
> +static void test_dontneed_before_mmap(int fd, struct
> +drm_xe_engine_class_instance *hwe) {
> + uint32_t bo, vm;
> + uint64_t addr = PURGEABLE_ADDR;
> + size_t bo_size = PURGEABLE_BO_SIZE;
> + void *map;
> +
> + purgeable_setup_simple_bo(fd, &vm, &bo, addr, bo_size, false);
> + if (!purgeable_mark_and_verify_purged(fd, vm, addr, bo_size))
> + igt_skip("Unable to induce purge on this platform/config");
> +
> + /* mmap the purged BO - access should trigger SIGBUS */
> + map = xe_bo_map(fd, bo, bo_size);
> +
> + {
> + sighandler_t old_sigsegv, old_sigbus;
> + char *ptr = (char *)map;
> + int sig;
> +
> + old_sigsegv = signal(SIGSEGV, (__sighandler_t)sigtrap);
> + old_sigbus = signal(SIGBUS, (__sighandler_t)sigtrap);
> +
> + sig = sigsetjmp(jmp, SIGBUS | SIGSEGV);
> + switch (sig) {
> + case SIGBUS:
> + case SIGSEGV:
> + /* Expected - purged BO access failed */
> + break;
> + case 0:
> + *ptr = 0;
> + __attribute__ ((fallthrough));
> + default:
> + igt_assert_f(false,
> + "Access to purged mmap should trigger
> SIGBUS, got sig=%d\n",
> + sig);
> + break;
> + }
> +
> + signal(SIGBUS, old_sigbus);
> + signal(SIGSEGV, old_sigsegv);
> + munmap(map, bo_size);
> + }
> +
> + gem_close(fd, bo);
> + xe_vm_destroy(fd, vm);
> +}
> +
> +int igt_main()
> +{
> + struct drm_xe_engine_class_instance *hwe;
> + int fd;
> +
> + igt_fixture() {
> + fd = drm_open_driver(DRIVER_XE);
> + xe_device_get(fd);
> + }
> +
> + igt_subtest("dontneed-before-mmap")
> + xe_for_each_engine(fd, hwe) {
> + test_dontneed_before_mmap(fd, hwe);
> + break;
> + }
> +
> + igt_fixture() {
> + xe_device_put(fd);
> + drm_close_driver(fd);
> + }
> +}
Reviewed-by: Pravalika Gurram <pravalika.gurram@intel.com>
> diff --git a/tests/meson.build b/tests/meson.build index
> 0ad728b87..9d41d7de6 100644
> --- a/tests/meson.build
> +++ b/tests/meson.build
> @@ -313,6 +313,7 @@ intel_xe_progs = [
> 'xe_huc_copy',
> 'xe_intel_bb',
> 'xe_live_ktest',
> + 'xe_madvise',
> 'xe_media_fill',
> 'xe_mmap',
> 'xe_module_load',
> --
> 2.43.0