[RFC PATCH v1 23/37] KVM: selftests: guest_memfd: Convert with allocated folios in different layouts
From: Ackerley Tng <hidden>
Date: 2025-10-17 20:13:10
Also in:
cgroups, kvm, linux-doc, linux-fsdevel, linux-kselftest, linux-mm, lkml
Subsystem:
kernel selftest framework, kernel virtual machine (kvm), the rest · Maintainers:
Shuah Khan, Paolo Bonzini, Linus Torvalds
Add a guest_memfd selftest to verify that memory conversions work correctly with allocated folios in different layouts. By iterating through which pages are initially faulted, the test covers various layouts of contiguous allocated and unallocated regions, exercising conversion with different range layouts. Signed-off-by: Ackerley Tng <redacted> Co-developed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> --- .../kvm/guest_memfd_conversions_test.c | 30 +++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/tools/testing/selftests/kvm/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/guest_memfd_conversions_test.c
index 3b222009227c3..b42b1b27cb727 100644
--- a/tools/testing/selftests/kvm/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_conversions_test.c@@ -277,6 +277,36 @@ GMEM_CONVERSION_TEST_INIT_PRIVATE(before_allocation_private) test_convert_to_shared(t, 0, 0, 'A', 'B'); } +/* + * Test that when some of the folios in the conversion range are allocated, + * conversion requests are handled correctly in guest_memfd. Vary the ranges + * allocated before conversion, using test_page, to cover various layouts of + * contiguous allocated and unallocated regions. + */ +GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED(unallocated_folios, 8) +{ + const int second_page_to_fault = 4; + int i; + + /* + * Fault 2 of the pages to test filemap range operations except when + * test_page == second_page_to_fault. + */ + host_do_rmw(t->mem, test_page, 0, 'A'); + if (test_page != second_page_to_fault) + host_do_rmw(t->mem, second_page_to_fault, 0, 'A'); + + gmem_set_private(t->gmem_fd, 0, nr_pages * page_size); + for (i = 0; i < nr_pages; ++i) { + char expected = (i == test_page || i == second_page_to_fault) ? 'A' : 0; + + test_private(t, i, expected, 'B'); + } + + for (i = 0; i < nr_pages; ++i) + test_convert_to_shared(t, i, 'B', 'C', 'D'); +} + int main(int argc, char *argv[]) { TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));
--
2.51.0.858.gf9c4a03a3a-goog