Re: [PATCH 2/4] KVM: s390: selftests: Use TAP interface in the sync_regs test

[Thomas Huth <thuth@redhat.com>]

On 14/04/2022 13.39, Claudio Imbrenda wrote:
> On Thu, 14 Apr 2022 12:53:20 +0200
> Thomas Huth <thuth@redhat.com> wrote:
> 
>> The sync_regs test currently does not have any output (unless one
>> of the TEST_ASSERT statement fails), so it's hard to say for a user
>> whether a certain new sub-test has been included in the binary or
>> not. Let's make this a little bit more user-friendly and include
>> some TAP output via the kselftests.h interface.
>> To be able to distinguish the different sub-tests more easily, we
>> also break up the huge main() function here in more fine grained
>> parts.
>>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>   .../selftests/kvm/s390x/sync_regs_test.c      | 86 ++++++++++++++-----
>>   1 file changed, 65 insertions(+), 21 deletions(-)
>>
>> diff --git a/tools/testing/selftests/kvm/s390x/sync_regs_test.c b/tools/testing/selftests/kvm/s390x/sync_regs_test.c
>> index caf7b8859a94..d5ddcbb82d12 100644
>> --- a/tools/testing/selftests/kvm/s390x/sync_regs_test.c
>> +++ b/tools/testing/selftests/kvm/s390x/sync_regs_test.c
>> @@ -21,6 +21,7 @@
>>   #include "test_util.h"
>>   #include "kvm_util.h"
>>   #include "diag318_test_handler.h"
>> +#include "kselftest.h"
>>   
>>   #define VCPU_ID 5
>>   
>> @@ -74,27 +75,9 @@ static void compare_sregs(struct kvm_sregs *left, struct kvm_sync_regs *right)
>>   #define TEST_SYNC_FIELDS   (KVM_SYNC_GPRS|KVM_SYNC_ACRS|KVM_SYNC_CRS|KVM_SYNC_DIAG318)
>>   #define INVALID_SYNC_FIELD 0x80000000
>>   
>> -int main(int argc, char *argv[])
>> +void test_read_invalid(struct kvm_vm *vm, struct kvm_run *run)
>>   {
>> -	struct kvm_vm *vm;
>> -	struct kvm_run *run;
>> -	struct kvm_regs regs;
>> -	struct kvm_sregs sregs;
>> -	int rv, cap;
>> -
>> -	/* Tell stdout not to buffer its content */
>> -	setbuf(stdout, NULL);
>> -
>> -	cap = kvm_check_cap(KVM_CAP_SYNC_REGS);
>> -	if (!cap) {
>> -		print_skip("CAP_SYNC_REGS not supported");
>> -		exit(KSFT_SKIP);
>> -	}
>> -
>> -	/* Create VM */
>> -	vm = vm_create_default(VCPU_ID, 0, guest_code);
>> -
>> -	run = vcpu_state(vm, VCPU_ID);
>> +	int rv;
>>   
>>   	/* Request reading invalid register set from VCPU. */
>>   	run->kvm_valid_regs = INVALID_SYNC_FIELD;
>> @@ -110,6 +93,11 @@ int main(int argc, char *argv[])
>>   		    "Invalid kvm_valid_regs did not cause expected KVM_RUN error: %d\n",
>>   		    rv);
>>   	vcpu_state(vm, VCPU_ID)->kvm_valid_regs = 0;
>> +}
>> +
>> +void test_set_invalid(struct kvm_vm *vm, struct kvm_run *run)
>> +{
>> +	int rv;
>>   
>>   	/* Request setting invalid register set into VCPU. */
>>   	run->kvm_dirty_regs = INVALID_SYNC_FIELD;
>> @@ -125,6 +113,13 @@ int main(int argc, char *argv[])
>>   		    "Invalid kvm_dirty_regs did not cause expected KVM_RUN error: %d\n",
>>   		    rv);
>>   	vcpu_state(vm, VCPU_ID)->kvm_dirty_regs = 0;
>> +}
>> +
>> +void test_req_and_verify_all_valid_regs(struct kvm_vm *vm, struct kvm_run *run)
>> +{
>> +	struct kvm_sregs sregs;
>> +	struct kvm_regs regs;
>> +	int rv;
>>   
>>   	/* Request and verify all valid register sets. */
>>   	run->kvm_valid_regs = TEST_SYNC_FIELDS;
>> @@ -146,6 +141,13 @@ int main(int argc, char *argv[])
>>   
>>   	vcpu_sregs_get(vm, VCPU_ID, &sregs);
>>   	compare_sregs(&sregs, &run->s.regs);
>> +}
>> +
>> +void test_set_and_verify_various_reg_values(struct kvm_vm *vm, struct kvm_run *run)
>> +{
>> +	struct kvm_sregs sregs;
>> +	struct kvm_regs regs;
>> +	int rv;
>>   
>>   	/* Set and verify various register values */
>>   	run->s.regs.gprs[11] = 0xBAD1DEA;
>> @@ -180,6 +182,11 @@ int main(int argc, char *argv[])
>>   
>>   	vcpu_sregs_get(vm, VCPU_ID, &sregs);
>>   	compare_sregs(&sregs, &run->s.regs);
>> +}
>> +
>> +void test_clear_kvm_dirty_regs_bits(struct kvm_vm *vm, struct kvm_run *run)
>> +{
>> +	int rv;
>>   
>>   	/* Clear kvm_dirty_regs bits, verify new s.regs values are
>>   	 * overwritten with existing guest values.
>> @@ -200,8 +207,45 @@ int main(int argc, char *argv[])
>>   	TEST_ASSERT(run->s.regs.diag318 != 0x4B1D,
>>   		    "diag318 sync regs value incorrect 0x%llx.",
>>   		    run->s.regs.diag318);
>> +}
>> +
>> +struct testdef {
>> +	const char *name;
>> +	void (*test)(struct kvm_vm *vm, struct kvm_run *run);
>> +} testlist[] = {
>> +	{ "read invalid", test_read_invalid },
>> +	{ "set invalid", test_set_invalid },
>> +	{ "request+verify all valid regs", test_req_and_verify_all_valid_regs },
>> +	{ "set+verify various regs", test_set_and_verify_various_reg_values },
>> +	{ "clear kvm_dirty_regs bits", test_clear_kvm_dirty_regs_bits },
>> +};
>> +
>> +int main(int argc, char *argv[])
>> +{
>> +	static struct kvm_run *run;
>> +	static struct kvm_vm *vm;
>> +	int idx;
>> +
>> +	/* Tell stdout not to buffer its content */
>> +	setbuf(stdout, NULL);
>> +
>> +	if (!kvm_check_cap(KVM_CAP_SYNC_REGS))
>> +		ksft_exit_skip("CAP_SYNC_REGS not supported");
> 
> I'm not an expert on the TAP format, but wouldn't it be more meaningful
> to print the header first? (like you do in the previous patch)

It shouldn't matter much, without the header, TAP version 12 will be used:

  https://testanything.org/tap-specification.html

With header, it switches to version 13:

  https://testanything.org/tap-version-13-specification.html

But the "1..0" lines (which signal a complete skip) are part of both 
versions, so we should be fine here.

(but I can also move it in case I have to respin anyway)

  Thomas