Starting state migration after an IO exit without first completing IO may result in test failures. We already have two tests that need this (this patch in fact fixes evmcs_test, similar to what was fixed for state_test in commit 0f73bbc851ed, "KVM: selftests: complete IO before migrating guest state", 2019-03-13) and a third is coming. So, move the code to vcpu_save_state, and while at it do not access register state until after I/O is complete. --- tools/testing/selftests/kvm/lib/kvm_util.c | 5 +++++ tools/testing/selftests/kvm/lib/x86_64/processor.c | 8 ++++++++ tools/testing/selftests/kvm/x86_64/evmcs_test.c | 5 +++-- tools/testing/selftests/kvm/x86_64/state_test.c | 15 +-------------- 4 files changed, 17 insertions(+), 16 deletions(-) diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index efa0aad8b3c6..4ca96b228e46 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -91,6 +91,11 @@ static void vm_open(struct kvm_vm *vm, int perm, unsigned long type) if (vm->kvm_fd < 0) exit(KSFT_SKIP); + if (!kvm_check_cap(KVM_CAP_IMMEDIATE_EXIT)) { + fprintf(stderr, "immediate_exit not available, skipping test\n"); + exit(KSFT_SKIP); + } + vm->fd = ioctl(vm->kvm_fd, KVM_CREATE_VM, type); TEST_ASSERT(vm->fd >= 0, "KVM_CREATE_VM ioctl failed, " "rc: %i errno: %i", vm->fd, errno); diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index f28127f4a3af..b363c9611bd6 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -1030,6 +1030,14 @@ struct kvm_x86_state *vcpu_save_state(struct kvm_vm *vm, uint32_t vcpuid) nested_size, sizeof(state->nested_)); } + /* + * When KVM exits to userspace with KVM_EXIT_IO, KVM guarantees + * guest state is consistent only after userspace re-enters the + * kernel with KVM_RUN. Complete IO prior to migrating state + * to a new VM. + */ + vcpu_run_complete_io(vm, vcpuid); + nmsrs = kvm_get_num_msrs(vm); list = malloc(sizeof(*list) + nmsrs * sizeof(list->indices[0])); list->nmsrs = nmsrs; diff --git a/tools/testing/selftests/kvm/x86_64/evmcs_test.c b/tools/testing/selftests/kvm/x86_64/evmcs_test.c index c49c2a28b0eb..36669684eca5 100644 --- a/tools/testing/selftests/kvm/x86_64/evmcs_test.c +++ b/tools/testing/selftests/kvm/x86_64/evmcs_test.c @@ -123,8 +123,6 @@ int main(int argc, char *argv[]) stage, run->exit_reason, exit_reason_str(run->exit_reason)); - memset(®s1, 0, sizeof(regs1)); - vcpu_regs_get(vm, VCPU_ID, ®s1); switch (get_ucall(vm, VCPU_ID, &uc)) { case UCALL_ABORT: TEST_ASSERT(false, "%s at %s:%d", (const char *)uc.args[0], @@ -144,6 +142,9 @@ int main(int argc, char *argv[]) stage, (ulong)uc.args[1]); state = vcpu_save_state(vm, VCPU_ID); + memset(®s1, 0, sizeof(regs1)); + vcpu_regs_get(vm, VCPU_ID, ®s1); + kvm_vm_release(vm); /* Restore state in a new VM. */ diff --git a/tools/testing/selftests/kvm/x86_64/state_test.c b/tools/testing/selftests/kvm/x86_64/state_test.c index 30f75856cf39..e0a3c0204b7c 100644 --- a/tools/testing/selftests/kvm/x86_64/state_test.c +++ b/tools/testing/selftests/kvm/x86_64/state_test.c @@ -134,11 +134,6 @@ int main(int argc, char *argv[]) struct kvm_cpuid_entry2 *entry = kvm_get_supported_cpuid_entry(1); - if (!kvm_check_cap(KVM_CAP_IMMEDIATE_EXIT)) { - fprintf(stderr, "immediate_exit not available, skipping test\n"); - exit(KSFT_SKIP); - } - /* Create VM */ vm = vm_create_default(VCPU_ID, 0, guest_code); vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid()); @@ -179,18 +174,10 @@ int main(int argc, char *argv[]) uc.args[1] == stage, "Unexpected register values vmexit #%lx, got %lx", stage, (ulong)uc.args[1]); - /* - * When KVM exits to userspace with KVM_EXIT_IO, KVM guarantees - * guest state is consistent only after userspace re-enters the - * kernel with KVM_RUN. Complete IO prior to migrating state - * to a new VM. - */ - vcpu_run_complete_io(vm, VCPU_ID); - + state = vcpu_save_state(vm, VCPU_ID); memset(®s1, 0, sizeof(regs1)); vcpu_regs_get(vm, VCPU_ID, ®s1); - state = vcpu_save_state(vm, VCPU_ID); kvm_vm_release(vm); /* Restore state in a new VM. */ -- 1.8.3.1