On Tue, 9 Jul 2024 14:56:58 +0200
Christoph Schlameuss <schlameuss@xxxxxxxxxxxxx> wrote:
> Add test suite to validate the s390x architecture specific ucontrol KVM
> interface.
>
> Make use of the selftest test harness.
>
> * uc_cap_hpage testcase verifies that a ucontrol VM cannot be run with
> hugepages.
>
> To allow testing of the ucontrol interface the kernel needs a
> non-default config containing CONFIG_KVM_S390_UCONTROL.
> This config needs to be set to built-in (y) as this cannot be built as
> module.
>
> Signed-off-by: Christoph Schlameuss <schlameuss@xxxxxxxxxxxxx>
Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
> ---
> tools/testing/selftests/kvm/.gitignore | 1 +
> tools/testing/selftests/kvm/Makefile | 1 +
> tools/testing/selftests/kvm/s390x/config | 2 +
> .../selftests/kvm/s390x/ucontrol_test.c | 78 +++++++++++++++++++
> 4 files changed, 82 insertions(+)
> create mode 100644 tools/testing/selftests/kvm/s390x/config
> create mode 100644 tools/testing/selftests/kvm/s390x/ucontrol_test.c
>
> diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
> index 6d9381d60172..f2a30a58cd71 100644
> --- a/tools/testing/selftests/kvm/.gitignore
> +++ b/tools/testing/selftests/kvm/.gitignore
> @@ -5,3 +5,4 @@
> !*.h
> !*.S
> !*.sh
> +!config
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index ac280dcba996..3b33b3975c93 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -184,6 +184,7 @@ TEST_GEN_PROGS_s390x += s390x/tprot
> TEST_GEN_PROGS_s390x += s390x/cmma_test
> TEST_GEN_PROGS_s390x += s390x/debug_test
> TEST_GEN_PROGS_s390x += s390x/shared_zeropage_test
> +TEST_GEN_PROGS_s390x += s390x/ucontrol_test
> TEST_GEN_PROGS_s390x += demand_paging_test
> TEST_GEN_PROGS_s390x += dirty_log_test
> TEST_GEN_PROGS_s390x += guest_print_test
> diff --git a/tools/testing/selftests/kvm/s390x/config b/tools/testing/selftests/kvm/s390x/config
> new file mode 100644
> index 000000000000..23270f2d679f
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/s390x/config
> @@ -0,0 +1,2 @@
> +CONFIG_KVM=y
> +CONFIG_KVM_S390_UCONTROL=y
> diff --git a/tools/testing/selftests/kvm/s390x/ucontrol_test.c b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
> new file mode 100644
> index 000000000000..a706a9f2b9ea
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
> @@ -0,0 +1,78 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Test code for the s390x kvm ucontrol interface
> + *
> + * Copyright IBM Corp. 2024
> + *
> + * Authors:
> + * Christoph Schlameuss <schlameuss@xxxxxxxxxxxxx>
> + */
> +#include "kselftest_harness.h"
> +#include "kvm_util.h"
> +
> +#include <linux/capability.h>
> +#include <linux/sizes.h>
> +
> +#define SYS_ADMIN_CAP 0x200000
> +
> +/* so directly declare capget to check caps without libcap */
> +int capget(cap_user_header_t header, cap_user_data_t data);
> +
> +/**
> + * In order to create user controlled virtual machines on S390,
> + * check KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL
> + * as privileged user (SYS_ADMIN).
> + */
> +void require_ucontrol_admin(void)
> +{
> + struct __user_cap_data_struct data[_LINUX_CAPABILITY_U32S_3];
> + struct __user_cap_header_struct hdr = {
> + .version = _LINUX_CAPABILITY_VERSION_3,
> + };
> + int rc;
> +
> + rc = capget(&hdr, data);
> + TEST_ASSERT_EQ(0, rc);
> + TEST_REQUIRE((data->effective & SYS_ADMIN_CAP) > 0);
> +
> + TEST_REQUIRE(kvm_has_cap(KVM_CAP_S390_UCONTROL));
> +}
> +
> +/**
> + * Assert HPAGE CAP cannot be enabled on UCONTROL VM
> + */
> +TEST(uc_cap_hpage)
> +{
> + int rc, kvm_fd, vm_fd, vcpu_fd;
> + struct kvm_enable_cap cap = {
> + .cap = KVM_CAP_S390_HPAGE_1M,
> + };
> +
> + require_ucontrol_admin();
> +
> + kvm_fd = open_kvm_dev_path_or_exit();
> + vm_fd = ioctl(kvm_fd, KVM_CREATE_VM, KVM_VM_S390_UCONTROL);
> + ASSERT_GE(vm_fd, 0);
> +
> + /* assert hpages are not supported on ucontrol vm */
> + rc = ioctl(vm_fd, KVM_CHECK_EXTENSION, KVM_CAP_S390_HPAGE_1M);
> + EXPECT_EQ(0, rc);
> +
> + /* Test that KVM_CAP_S390_HPAGE_1M can't be enabled for a ucontrol vm */
> + rc = ioctl(vm_fd, KVM_ENABLE_CAP, cap);
> + EXPECT_EQ(-1, rc);
> + EXPECT_EQ(EINVAL, errno);
> +
> + /* assert HPAGE CAP is rejected after vCPU creation */
> + vcpu_fd = ioctl(vm_fd, KVM_CREATE_VCPU, 0);
> + ASSERT_GE(vcpu_fd, 0);
> + rc = ioctl(vm_fd, KVM_ENABLE_CAP, cap);
> + EXPECT_EQ(-1, rc);
> + EXPECT_EQ(EBUSY, errno);
> +
> + close(vcpu_fd);
> + close(vm_fd);
> + close(kvm_fd);
> +}
> +
> +TEST_HARNESS_MAIN
