[PATCH i-g-t v6 4/9] tests/intel/xe_madvise: Add purged-mmap-blocked subtest

[Arvind Yadav <arvind.yadav@intel.com>]

Add a new purged-mmap-blocked subtest that triggers an actual purge
via memory pressure and verifies that mmap() fails with -EINVAL once
the BO backing store has been permanently discarded.

The purgeable check moved from xe_gem_mmap_offset_ioctl()
into a new xe_gem_object_mmap() callback, so the blocking point is now
mmap() itself rather than the mmap offset ioctl:

  - DRM_IOCTL_XE_GEM_MMAP_OFFSET: always succeeds regardless of
    purgeable state (just returns the pre-allocated offset)
  - mmap() on DONTNEED BO: fails with -EBUSY (temporary state)
  - mmap() on purged BO: fails with -EINVAL (permanent, no backing store)

v5:
  - Add purged-mmap-blocked subtest to verify mmap is blocked after
    BO backing store is permanently purged.

v6:
  - DRM_IOCTL_XE_GEM_MMAP_OFFSET always succeeds; the purgeable check
    now happens in xe_gem_object_mmap() at mmap() time. For purged BOs,
    assert mmap() fails with -EINVAL.

Cc: Nishit Sharma <nishit.sharma@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>
Cc: Pravalika Gurram <pravalika.gurram@intel.com>
Signed-off-by: Arvind Yadav <arvind.yadav@intel.com>
---
 tests/intel/xe_madvise.c | 42 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/tests/intel/xe_madvise.c b/tests/intel/xe_madvise.c
index de4a6e34c..81e05b6d4 100644
--- a/tests/intel/xe_madvise.c
+++ b/tests/intel/xe_madvise.c
@@ -170,6 +170,42 @@ static void purgeable_setup_simple_bo(int fd, uint32_t *vm, uint32_t *bo,
 	xe_wait_ufence(fd, &sync_val, 1, 0, NSEC_PER_SEC);
 }
 
+/**
+ * SUBTEST: purged-mmap-blocked
+ * Description: After BO is purged, verify mmap() fails with -EINVAL
+ * Test category: functionality test
+ */
+static void test_purged_mmap_blocked(int fd)
+{
+	uint32_t bo, vm;
+	uint64_t addr = PURGEABLE_ADDR;
+	size_t bo_size = PURGEABLE_BO_SIZE;
+	struct drm_xe_gem_mmap_offset mmo = {};
+	void *ptr;
+
+	purgeable_setup_simple_bo(fd, &vm, &bo, addr, bo_size, false);
+	if (!purgeable_mark_and_verify_purged(fd, vm, addr, bo_size)) {
+		gem_close(fd, bo);
+		xe_vm_destroy(fd, vm);
+		igt_skip("Unable to induce purge on this platform/config");
+	}
+
+	/*
+	 * Getting the mmap offset is always allowed regardless of purgeable
+	 * state - the blocking happens at mmap() time (xe_gem_object_mmap).
+	 * For a purged BO, mmap() must fail with -EINVAL (no backing store).
+	 */
+	mmo.handle = bo;
+	igt_assert_eq(igt_ioctl(fd, DRM_IOCTL_XE_GEM_MMAP_OFFSET, &mmo), 0);
+
+	ptr = mmap(NULL, bo_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, mmo.offset);
+	igt_assert_eq_u64((uint64_t)ptr, (uint64_t)MAP_FAILED);
+	igt_assert_eq(errno, EINVAL);
+
+	gem_close(fd, bo);
+	xe_vm_destroy(fd, vm);
+}
+
 /**
  * SUBTEST: dontneed-before-mmap
  * Description: Mark BO as DONTNEED before mmap, verify mmap() fails with -EBUSY
@@ -226,6 +262,12 @@ int igt_main()
 			break;
 		}
 
+	igt_subtest("purged-mmap-blocked")
+		xe_for_each_engine(fd, hwe) {
+			test_purged_mmap_blocked(fd);
+			break;
+		}
+
 	igt_fixture() {
 		xe_device_put(fd);
 		drm_close_driver(fd);
-- 
2.43.0