diff options
Diffstat (limited to 'tools/testing/selftests/kvm/pre_fault_memory_test.c')
| -rw-r--r-- | tools/testing/selftests/kvm/pre_fault_memory_test.c | 131 |
1 files changed, 114 insertions, 17 deletions
diff --git a/tools/testing/selftests/kvm/pre_fault_memory_test.c b/tools/testing/selftests/kvm/pre_fault_memory_test.c index 0350a8896a2f..f04768c1d2e4 100644 --- a/tools/testing/selftests/kvm/pre_fault_memory_test.c +++ b/tools/testing/selftests/kvm/pre_fault_memory_test.c @@ -10,6 +10,7 @@ #include <test_util.h> #include <kvm_util.h> #include <processor.h> +#include <pthread.h> /* Arbitrarily chosen values */ #define TEST_SIZE (SZ_2M + PAGE_SIZE) @@ -30,18 +31,66 @@ static void guest_code(uint64_t base_gpa) GUEST_DONE(); } -static void pre_fault_memory(struct kvm_vcpu *vcpu, u64 gpa, u64 size, - u64 left) +struct slot_worker_data { + struct kvm_vm *vm; + u64 gpa; + uint32_t flags; + bool worker_ready; + bool prefault_ready; + bool recreate_slot; +}; + +static void *delete_slot_worker(void *__data) +{ + struct slot_worker_data *data = __data; + struct kvm_vm *vm = data->vm; + + WRITE_ONCE(data->worker_ready, true); + + while (!READ_ONCE(data->prefault_ready)) + cpu_relax(); + + vm_mem_region_delete(vm, TEST_SLOT); + + while (!READ_ONCE(data->recreate_slot)) + cpu_relax(); + + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, data->gpa, + TEST_SLOT, TEST_NPAGES, data->flags); + + return NULL; +} + +static void pre_fault_memory(struct kvm_vcpu *vcpu, u64 base_gpa, u64 offset, + u64 size, u64 expected_left, bool private) { struct kvm_pre_fault_memory range = { - .gpa = gpa, + .gpa = base_gpa + offset, .size = size, .flags = 0, }; - u64 prev; + struct slot_worker_data data = { + .vm = vcpu->vm, + .gpa = base_gpa, + .flags = private ? KVM_MEM_GUEST_MEMFD : 0, + }; + bool slot_recreated = false; + pthread_t slot_worker; int ret, save_errno; + u64 prev; + + /* + * Concurrently delete (and recreate) the slot to test KVM's handling + * of a racing memslot deletion with prefaulting. + */ + pthread_create(&slot_worker, NULL, delete_slot_worker, &data); - do { + while (!READ_ONCE(data.worker_ready)) + cpu_relax(); + + WRITE_ONCE(data.prefault_ready, true); + + for (;;) { prev = range.size; ret = __vcpu_ioctl(vcpu, KVM_PRE_FAULT_MEMORY, &range); save_errno = errno; @@ -49,18 +98,65 @@ static void pre_fault_memory(struct kvm_vcpu *vcpu, u64 gpa, u64 size, "%sexpecting range.size to change on %s", ret < 0 ? "not " : "", ret < 0 ? "failure" : "success"); - } while (ret >= 0 ? range.size : save_errno == EINTR); - TEST_ASSERT(range.size == left, - "Completed with %lld bytes left, expected %" PRId64, - range.size, left); + /* + * Immediately retry prefaulting if KVM was interrupted by an + * unrelated signal/event. + */ + if (ret < 0 && save_errno == EINTR) + continue; + + /* + * Tell the worker to recreate the slot in order to complete + * prefaulting (if prefault didn't already succeed before the + * slot was deleted) and/or to prepare for the next testcase. + * Wait for the worker to exit so that the next invocation of + * prefaulting is guaranteed to complete (assuming no KVM bugs). + */ + if (!slot_recreated) { + WRITE_ONCE(data.recreate_slot, true); + pthread_join(slot_worker, NULL); + slot_recreated = true; + + /* + * Retry prefaulting to get a stable result, i.e. to + * avoid seeing random EAGAIN failures. Don't retry if + * prefaulting already succeeded, as KVM disallows + * prefaulting with size=0, i.e. blindly retrying would + * result in test failures due to EINVAL. KVM should + * always return success if all bytes are prefaulted, + * i.e. there is no need to guard against EAGAIN being + * returned. + */ + if (range.size) + continue; + } + + /* + * All done if there are no remaining bytes to prefault, or if + * prefaulting failed (EINTR was handled above, and EAGAIN due + * to prefaulting a memslot that's being actively deleted should + * be impossible since the memslot has already been recreated). + */ + if (!range.size || ret < 0) + break; + } - if (left == 0) - __TEST_ASSERT_VM_VCPU_IOCTL(!ret, "KVM_PRE_FAULT_MEMORY", ret, vcpu->vm); + TEST_ASSERT(range.size == expected_left, + "Completed with %llu bytes left, expected %lu", + range.size, expected_left); + + /* + * Assert success if prefaulting the entire range should succeed, i.e. + * complete with no bytes remaining. Otherwise prefaulting should have + * failed due to ENOENT (due to RET_PF_EMULATE for emulated MMIO when + * no memslot exists). + */ + if (!expected_left) + TEST_ASSERT_VM_VCPU_IOCTL(!ret, KVM_PRE_FAULT_MEMORY, ret, vcpu->vm); else - /* No memory slot causes RET_PF_EMULATE. it results in -ENOENT. */ - __TEST_ASSERT_VM_VCPU_IOCTL(ret && save_errno == ENOENT, - "KVM_PRE_FAULT_MEMORY", ret, vcpu->vm); + TEST_ASSERT_VM_VCPU_IOCTL(ret && save_errno == ENOENT, + KVM_PRE_FAULT_MEMORY, ret, vcpu->vm); } static void __test_pre_fault_memory(unsigned long vm_type, bool private) @@ -97,9 +193,10 @@ static void __test_pre_fault_memory(unsigned long vm_type, bool private) if (private) vm_mem_set_private(vm, guest_test_phys_mem, TEST_SIZE); - pre_fault_memory(vcpu, guest_test_phys_mem, SZ_2M, 0); - pre_fault_memory(vcpu, guest_test_phys_mem + SZ_2M, PAGE_SIZE * 2, PAGE_SIZE); - pre_fault_memory(vcpu, guest_test_phys_mem + TEST_SIZE, PAGE_SIZE, PAGE_SIZE); + + pre_fault_memory(vcpu, guest_test_phys_mem, 0, SZ_2M, 0, private); + pre_fault_memory(vcpu, guest_test_phys_mem, SZ_2M, PAGE_SIZE * 2, PAGE_SIZE, private); + pre_fault_memory(vcpu, guest_test_phys_mem, TEST_SIZE, PAGE_SIZE, PAGE_SIZE, private); vcpu_args_set(vcpu, 1, guest_test_virt_mem); vcpu_run(vcpu); |