On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay <[email protected]> wrote: > > From: Ackerley Tng <[email protected]> > > 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 <[email protected]>
nit below, otherwise: Reviewed-by: Fuad Tabba <[email protected]> Cheers, /fuad > --- > 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?"); nit: should you close this/reset it to -1 after the tests? > + > + 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 > >
