[PATCH v8 38/46] KVM: selftests: Add helpers to pin pages with CONFIG_GUP_TEST
From: Ackerley Tng via B4 Relay <devnull+ackerleytng.google.com@kernel.org>
Date: 2026-06-19 00:31:51
Also in:
b4-sent, kvm, linux-coco, linux-kselftest, linux-mm, linux-trace-kernel, lkml
Subsystem:
kernel selftest framework, kernel virtual machine (kvm), the rest · Maintainers:
Shuah Khan, Paolo Bonzini, Linus Torvalds
From: Ackerley Tng <redacted> Add helper functions to allow KVM selftests to pin memory using CONFIG_GUP_TEST. This is useful for testing scenarios where some page has an increased refcount. such as in guest_memfd in-place conversion tests. The helpers open /sys/kernel/debug/gup_test and invoke the PIN_LONGTERM_TEST_START and PIN_LONGTERM_TEST_STOP ioctls. Since this functionality depends on the kernel being built with CONFIG_GUP_TEST, provide stub implementations that trigger a test failure if the configuration is missing. Signed-off-by: Ackerley Tng <redacted> --- tools/testing/selftests/kvm/include/kvm_util.h | 3 +++ tools/testing/selftests/kvm/lib/kvm_util.c | 23 +++++++++++++++++++++++ 2 files changed, 26 insertions(+)
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 323d06b5699ec..79ab64ac8b869 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h@@ -1195,6 +1195,9 @@ static inline int pin_self_to_any_cpu(void) return pin_task_to_any_cpu(pthread_self()); } +void pin_pages(void *vaddr, uint64_t size); +void unpin_pages(void); + void kvm_print_vcpu_pinning_help(void); void kvm_parse_vcpu_pinning(const char *pcpus_string, u32 vcpu_to_pcpu[], int nr_vcpus);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index b73817f7bc803..524ef97d634bf 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c@@ -18,6 +18,8 @@ #include <unistd.h> #include <linux/kernel.h> +#include "../../../../mm/gup_test.h" + #define KVM_UTIL_MIN_PFN 2 u32 guest_random_seed;
@@ -639,6 +641,27 @@ int __pin_task_to_cpu(pthread_t task, int cpu) return pthread_setaffinity_np(task, sizeof(cpuset), &cpuset); } +static int gup_test_fd = -1; + +void pin_pages(void *vaddr, uint64_t size) +{ + const struct pin_longterm_test args = { + .addr = (uint64_t)vaddr, + .size = size, + .flags = PIN_LONGTERM_TEST_FLAG_USE_WRITE, + }; + + gup_test_fd = __open_path_or_exit("/sys/kernel/debug/gup_test", O_RDWR, + "Is CONFIG_GUP_TEST enabled?"); + + TEST_ASSERT_EQ(ioctl(gup_test_fd, PIN_LONGTERM_TEST_START, &args), 0); +} + +void unpin_pages(void) +{ + TEST_ASSERT_EQ(ioctl(gup_test_fd, PIN_LONGTERM_TEST_STOP), 0); +} + static u32 parse_pcpu(const char *cpu_str, const cpu_set_t *allowed_mask) { u32 pcpu = atoi_non_negative("CPU number", cpu_str);
--
2.55.0.rc0.738.g0c8ab3ebcc-goog