Re: [PATCH 08/12] selftests: sev_migrate_tests: add tests for KVM_CAP_VM_COPY_ENC_CONTEXT_FROM
From: Peter Gonda
Date: Wed Dec 01 2021 - 13:11:09 EST
On Mon, Nov 22, 2021 at 5:50 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> I am putting the tests in sev_migrate_tests because the failure conditions are
> very similar and some of the setup code can be reused, too.
>
> The tests cover both successful creation of a mirror VM, and error
> conditions.
>
> Cc: Peter Gonda <pgonda@xxxxxxxxxx>
> Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> .../selftests/kvm/x86_64/sev_migrate_tests.c | 112 ++++++++++++++++--
> 1 file changed, 105 insertions(+), 7 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/sev_migrate_tests.c b/tools/testing/selftests/kvm/x86_64/sev_migrate_tests.c
> index 0cd7e2eaa895..d265cea5de85 100644
> --- a/tools/testing/selftests/kvm/x86_64/sev_migrate_tests.c
> +++ b/tools/testing/selftests/kvm/x86_64/sev_migrate_tests.c
> @@ -54,12 +54,15 @@ static struct kvm_vm *sev_vm_create(bool es)
> return vm;
> }
>
> -static struct kvm_vm *__vm_create(void)
> +static struct kvm_vm *aux_vm_create(bool with_vcpus)
> {
> struct kvm_vm *vm;
> int i;
>
> vm = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
> + if (!with_vcpus)
> + return vm;
> +
> for (i = 0; i < NR_MIGRATE_TEST_VCPUS; ++i)
> vm_vcpu_add(vm, i);
>
> @@ -93,7 +96,7 @@ static void test_sev_migrate_from(bool es)
>
> src_vm = sev_vm_create(es);
> for (i = 0; i < NR_MIGRATE_TEST_VMS; ++i)
> - dst_vms[i] = __vm_create();
> + dst_vms[i] = aux_vm_create(true);
>
> /* Initial migration from the src to the first dst. */
> sev_migrate_from(dst_vms[0]->fd, src_vm->fd);
> @@ -162,7 +165,7 @@ static void test_sev_migrate_parameters(void)
> sev_vm = sev_vm_create(/* es= */ false);
> sev_es_vm = sev_vm_create(/* es= */ true);
> vm_no_vcpu = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
> - vm_no_sev = __vm_create();
> + vm_no_sev = aux_vm_create(true);
> sev_es_vm_no_vmsa = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
> sev_ioctl(sev_es_vm_no_vmsa->fd, KVM_SEV_ES_INIT, NULL);
> vm_vcpu_add(sev_es_vm_no_vmsa, 1);
> @@ -203,11 +206,106 @@ static void test_sev_migrate_parameters(void)
> kvm_vm_free(vm_no_sev);
> }
>
> +static int __sev_mirror_create(int dst_fd, int src_fd)
> +{
> + struct kvm_enable_cap cap = {
> + .cap = KVM_CAP_VM_COPY_ENC_CONTEXT_FROM,
> + .args = { src_fd }
> + };
> +
> + return ioctl(dst_fd, KVM_ENABLE_CAP, &cap);
> +}
> +
> +
> +static void sev_mirror_create(int dst_fd, int src_fd)
> +{
> + int ret;
> +
> + ret = __sev_mirror_create(dst_fd, src_fd);
> + TEST_ASSERT(!ret, "Copying context failed, ret: %d, errno: %d\n", ret, errno);
> +}
> +
> +static void test_sev_mirror(bool es)
> +{
> + struct kvm_vm *src_vm, *dst_vm;
> + struct kvm_sev_launch_start start = {
> + .policy = es ? SEV_POLICY_ES : 0
> + };
> + int i;
> +
> + src_vm = sev_vm_create(es);
> + dst_vm = aux_vm_create(false);
> +
> + sev_mirror_create(dst_vm->fd, src_vm->fd);
> +
> + /* Check that we can complete creation of the mirror VM. */
> + for (i = 0; i < NR_MIGRATE_TEST_VCPUS; ++i)
> + vm_vcpu_add(dst_vm, i);
> + sev_ioctl(dst_vm->fd, KVM_SEV_LAUNCH_START, &start);
I don't think this should be called on the mirror and I think it
should be an error.
In is_cmd_allowed_from_mirror() KVM_SEV_LAUNCH_START should not be allowed:
if (cmd_id == KVM_SEV_LAUNCH_UPDATE_VMSA ||
cmd_id == KVM_SEV_GUEST_STATUS || cmd_id == KVM_SEV_DBG_DECRYPT ||
cmd_id == KVM_SEV_DBG_ENCRYPT)
return true;
This overrides the mirrored values and sets up the VM as a new SEV
context. I would have thought the sev_bind_asid() in
sev_launch_start() would fail because the asid is already used by the
source.
> + if (es)
> + sev_ioctl(dst_vm->fd, KVM_SEV_LAUNCH_UPDATE_VMSA, NULL);
> +
> + kvm_vm_free(src_vm);
> + kvm_vm_free(dst_vm);
> +}
> +
> +static void test_sev_mirror_parameters(void)
> +{
> + struct kvm_vm *sev_vm, *sev_es_vm, *vm_no_vcpu, *vm_with_vcpu;
> + int ret;
> +
> + sev_vm = sev_vm_create(/* es= */ false);
> + sev_es_vm = sev_vm_create(/* es= */ true);
> + vm_with_vcpu = aux_vm_create(true);
> + vm_no_vcpu = aux_vm_create(false);
> +
> + ret = __sev_mirror_create(sev_vm->fd, sev_vm->fd);
> + TEST_ASSERT(
> + ret == -1 && errno == EINVAL,
> + "Should not be able copy context to self. ret: %d, errno: %d\n",
> + ret, errno);
> +
> + ret = __sev_mirror_create(sev_vm->fd, sev_es_vm->fd);
> + TEST_ASSERT(
> + ret == -1 && errno == EINVAL,
> + "Should not be able copy context to SEV enabled VM. ret: %d, errno: %d\n",
> + ret, errno);
> +
> + ret = __sev_mirror_create(sev_es_vm->fd, sev_vm->fd);
> + TEST_ASSERT(
> + ret == -1 && errno == EINVAL,
> + "Should not be able copy context to SEV-ES enabled VM. ret: %d, errno: %d\n",
> + ret, errno);
> +
> + ret = __sev_mirror_create(vm_no_vcpu->fd, vm_with_vcpu->fd);
> + TEST_ASSERT(ret == -1 && errno == EINVAL,
> + "Copy context requires SEV enabled. ret %d, errno: %d\n", ret,
> + errno);
> +
> + ret = __sev_mirror_create(vm_with_vcpu->fd, sev_vm->fd);
> + TEST_ASSERT(
> + ret == -1 && errno == EINVAL,
> + "SEV copy context requires no vCPUS on the destination. ret: %d, errno: %d\n",
> + ret, errno);
> +
> + kvm_vm_free(sev_vm);
> + kvm_vm_free(sev_es_vm);
> + kvm_vm_free(vm_with_vcpu);
> + kvm_vm_free(vm_no_vcpu);
> +}
> +
> int main(int argc, char *argv[])
> {
> - test_sev_migrate_from(/* es= */ false);
> - test_sev_migrate_from(/* es= */ true);
> - test_sev_migrate_locking();
> - test_sev_migrate_parameters();
> + if (kvm_check_cap(KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM)) {
> + test_sev_migrate_from(/* es= */ false);
> + test_sev_migrate_from(/* es= */ true);
> + test_sev_migrate_locking();
> + test_sev_migrate_parameters();
> + }
> + if (kvm_check_cap(KVM_CAP_VM_COPY_ENC_CONTEXT_FROM)) {
> + test_sev_mirror(/* es= */ false);
> + test_sev_mirror(/* es= */ true);
> + test_sev_mirror_parameters();
> + }
> return 0;
> }
> --
> 2.27.0
>
>