On Wed, 24 Jul 2024 16:52:00 +0200 Janosch Frank frankja@linux.ibm.com wrote:
On 7/23/24 11:31, Christoph Schlameuss 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@linux.ibm.com Reviewed-by: Claudio Imbrenda imbrenda@linux.ibm.com
[...]
+#include "kselftest_harness.h" +#include "kvm_util.h"
+#include <linux/capability.h> +#include <linux/sizes.h>
+#define SYS_ADMIN_CAP 0x200000
This looked suspicious to me. Surely this would be available in some form in capability.h since CAP_SYS_ADMIN is something that's regularly checked.
[...]
+/* 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);
And in fact capability.h does have defines which hide the magic constant: data->effective & CAP_TO_MASK(CAP_SYS_ADMIN)
Yes, thank you, that is much better. Will use that instead and remove the custom SYS_ADMIN_CAP define above.
- TEST_REQUIRE(kvm_has_cap(KVM_CAP_S390_UCONTROL));
+}