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KVM: selftests: Test guest_memfd binding overlap without GPA overlap

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The guest_memfd binding overlap test recreates the deleted slot with GPA
ranges that overlap the still-live slot.  KVM rejects those attempts from
the generic memslot overlap check before reaching kvm_gmem_bind(), so the
test can pass even if guest_memfd binding overlap detection is broken.

Recreate the slot at its original, non-overlapping GPA and use guest_memfd
offsets that overlap the front and back halves of the other slot's binding.
Expand the guest_memfd so the back-half case remains within the file size.

Fixes: 2feabb855d ("KVM: selftests: Expand set_memory_region_test to validate guest_memfd()")
Signed-off-by: Zongyao Chen <ZongYao.Chen@linux.alibaba.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
[sean: keep the existing GPA overlap testcases]
Link: https://patch.msgid.link/20260522172151.3530267-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Zongyao Chen 2026-05-22 10:21:50 -07:00 committed by Sean Christopherson
parent 7ea987a905
commit 772989854a
1 changed files with 25 additions and 2 deletions
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27
tools/testing/selftests/kvm/set_memory_region_test.c
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@ -510,7 +510,7 @@ static void test_add_overlapping_private_memory_regions(void)
vm = vm_create_barebones_type(KVM_X86_SW_PROTECTED_VM);
memfd = vm_create_guest_memfd(vm, MEM_REGION_SIZE * 4, 0);
memfd = vm_create_guest_memfd(vm, MEM_REGION_SIZE * 5, 0);
vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
MEM_REGION_GPA, MEM_REGION_SIZE * 2, 0, memfd, 0);
@ -526,7 +526,30 @@ static void test_add_overlapping_private_memory_regions(void)
vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
MEM_REGION_GPA, 0, NULL, -1, 0);
/* Overlap the front half of the other slot. */
/*
* Verify that overlap in the guest_memfd bindings (i.e. in guest_memfd
* file offsets), but _not_ in the GPA space, fails with -EEXIST.
*/
r = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
MEM_REGION_GPA,
MEM_REGION_SIZE * 2,
0, memfd, MEM_REGION_SIZE);
TEST_ASSERT(r == -1 && errno == EEXIST,
"Overlapping guest_memfd() bindings should fail with EEXIST");
/* And now the back half of the other slot's guest_memfd binding. */
r = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
MEM_REGION_GPA,
MEM_REGION_SIZE * 2,
0, memfd, MEM_REGION_SIZE * 3);
TEST_ASSERT(r == -1 && errno == EEXIST,
"Overlapping guest_memfd() bindings should fail with EEXIST");
/*
* Repeat the overlap tests, but this time with overlap in the memslots
* GPA space. Regardless of where there is overlap, KVM should return
* -EEXIST.
*/
r = __vm_set_user_memory_region2(vm, MEM_REGION_SLOT, KVM_MEM_GUEST_MEMFD,
MEM_REGION_GPA * 2 - MEM_REGION_SIZE,
MEM_REGION_SIZE * 2,