Re: [PATCH v8 3/4] selftests: KVM: s390x: Add reset tests

[Janosch Frank <frankja@linux.ibm.com>]

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On 1/30/20 11:51 AM, Thomas Huth wrote:
> On 29/01/2020 21.03, Janosch Frank wrote:
>> Test if the registers end up having the correct values after a normal,
>> initial and clear reset.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>  tools/testing/selftests/kvm/Makefile       |   1 +
>>  tools/testing/selftests/kvm/s390x/resets.c | 165 +++++++++++++++++++++
>>  2 files changed, 166 insertions(+)
>>  create mode 100644 tools/testing/selftests/kvm/s390x/resets.c
>>
>> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
>> index 3138a916574a..fe1ea294730c 100644
>> --- a/tools/testing/selftests/kvm/Makefile
>> +++ b/tools/testing/selftests/kvm/Makefile
>> @@ -36,6 +36,7 @@ TEST_GEN_PROGS_aarch64 += kvm_create_max_vcpus
>>  
>>  TEST_GEN_PROGS_s390x = s390x/memop
>>  TEST_GEN_PROGS_s390x += s390x/sync_regs_test
>> +TEST_GEN_PROGS_s390x += s390x/resets
>>  TEST_GEN_PROGS_s390x += dirty_log_test
>>  TEST_GEN_PROGS_s390x += kvm_create_max_vcpus
>>  
>> diff --git a/tools/testing/selftests/kvm/s390x/resets.c b/tools/testing/selftests/kvm/s390x/resets.c
>> new file mode 100644
>> index 000000000000..2b2378cc9e80
>> --- /dev/null
>> +++ b/tools/testing/selftests/kvm/s390x/resets.c
>> @@ -0,0 +1,165 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Test for s390x CPU resets
>> + *
>> + * Copyright (C) 2020, IBM
>> + */
>> +
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +#include <sys/ioctl.h>
>> +
>> +#include "test_util.h"
>> +#include "kvm_util.h"
>> +
>> +#define VCPU_ID 3
>> +
>> +struct kvm_vm *vm;
>> +struct kvm_run *run;
>> +struct kvm_sync_regs *regs;
>> +static uint64_t regs_null[16];
>> +
>> +static uint64_t crs[16] = { 0x40000ULL,
>> +			    0x42000ULL,
>> +			    0, 0, 0, 0, 0,
>> +			    0x43000ULL,
>> +			    0, 0, 0, 0, 0,
>> +			    0x44000ULL,
>> +			    0, 0
>> +};
>> +
>> +static void guest_code_initial(void)
>> +{
>> +	/* Round toward 0 */
>> +	uint32_t fpc = 0x11;
>> +
>> +	/* Dirty registers */
>> +	asm volatile (
>> +		"	lctlg	0,15,%0\n"
>> +		"	sfpc	%1\n"
>> +		: : "Q" (crs), "d" (fpc));
> 
> I'd recommend to add a GUEST_SYNC(0) here ... otherwise the guest code
> tries to return from this function and will cause a crash - which will
> also finish execution of the guest, but might have unexpected side effects.

Ok

> 
>> +}
>> +
>> +static void test_one_reg(uint64_t id, uint64_t value)
>> +{
>> +	struct kvm_one_reg reg;
>> +	uint64_t eval_reg;
>> +
>> +	reg.addr = (uintptr_t)&eval_reg;
>> +	reg.id = id;
>> +	vcpu_get_reg(vm, VCPU_ID, &reg);
>> +	TEST_ASSERT(eval_reg == value, "value == %s", value);
>> +}
>> +
>> +static void assert_clear(void)
>> +{
>> +	struct kvm_sregs sregs;
>> +	struct kvm_regs regs;
>> +	struct kvm_fpu fpu;
>> +
>> +	vcpu_regs_get(vm, VCPU_ID, &regs);
>> +	TEST_ASSERT(!memcmp(&regs.gprs, regs_null, sizeof(regs.gprs)), "grs == 0");
>> +
>> +	vcpu_sregs_get(vm, VCPU_ID, &sregs);
>> +	TEST_ASSERT(!memcmp(&sregs.acrs, regs_null, sizeof(sregs.acrs)), "acrs == 0");
>> +
>> +	vcpu_fpu_get(vm, VCPU_ID, &fpu);
>> +	TEST_ASSERT(!memcmp(&fpu.fprs, regs_null, sizeof(fpu.fprs)), "fprs == 0");
>> +}
>> +
>> +static void assert_initial(void)
>> +{
>> +	struct kvm_sregs sregs;
>> +	struct kvm_fpu fpu;
>> +
>> +	vcpu_sregs_get(vm, VCPU_ID, &sregs);
>> +	TEST_ASSERT(sregs.crs[0] == 0xE0UL, "cr0 == 0xE0");
>> +	TEST_ASSERT(sregs.crs[14] == 0xC2000000UL, "cr14 == 0xC2000000");
>> +	TEST_ASSERT(!memcmp(&sregs.crs[1], regs_null, sizeof(sregs.crs[1]) * 12),
>> +		    "cr1-13 == 0");
>> +	TEST_ASSERT(sregs.crs[15] == 0, "cr15 == 0");
>> +
>> +	vcpu_fpu_get(vm, VCPU_ID, &fpu);
>> +	TEST_ASSERT(!fpu.fpc, "fpc == 0");
>> +
>> +	test_one_reg(KVM_REG_S390_GBEA, 1);
>> +	test_one_reg(KVM_REG_S390_PP, 0);
>> +	test_one_reg(KVM_REG_S390_TODPR, 0);
>> +	test_one_reg(KVM_REG_S390_CPU_TIMER, 0);
>> +	test_one_reg(KVM_REG_S390_CLOCK_COMP, 0);
>> +}
>> +
>> +static void assert_normal(void)
>> +{
>> +	test_one_reg(KVM_REG_S390_PFTOKEN, KVM_S390_PFAULT_TOKEN_INVALID);
>> +}
>> +
>> +static void test_normal(void)
>> +{
>> +	printf("Testing notmal reset\n");
>> +	/* Create VM */
>> +	vm = vm_create_default(VCPU_ID, 0, guest_code_initial);
>> +	run = vcpu_state(vm, VCPU_ID);
>> +	regs = &run->s.regs;
>> +
>> +	_vcpu_run(vm, VCPU_ID);
> 
> Could you use vcpu_run() instead of _vcpu_run() ?

Done.

> 
>> +	vcpu_ioctl(vm, VCPU_ID, KVM_S390_NORMAL_RESET, 0);
>> +	assert_normal();
>> +	kvm_vm_free(vm);
>> +}
>> +
>> +static int test_initial(void)
>> +{
>> +	int rv;
>> +
>> +	printf("Testing initial reset\n");
>> +	/* Create VM */
>> +	vm = vm_create_default(VCPU_ID, 0, guest_code_initial);
>> +	run = vcpu_state(vm, VCPU_ID);
>> +	regs = &run->s.regs;
>> +
>> +	rv = _vcpu_run(vm, VCPU_ID);
> 
> Extra bonus points if you check here that the registers contain the
> values that have been set by the guest ;-)

I started working on that yesterday

> 
>> +	vcpu_ioctl(vm, VCPU_ID, KVM_S390_INITIAL_RESET, 0);
>> +	assert_normal();
>> +	assert_initial();
>> +	kvm_vm_free(vm);
>> +	return rv;
>> +}
>> +
>> +static int test_clear(void)
>> +{
>> +	int rv;
>> +
>> +	printf("Testing clear reset\n");
>> +	/* Create VM */
>> +	vm = vm_create_default(VCPU_ID, 0, guest_code_initial);
>> +	run = vcpu_state(vm, VCPU_ID);
>> +	regs = &run->s.regs;
>> +
>> +	rv = _vcpu_run(vm, VCPU_ID);
>> +
>> +	vcpu_ioctl(vm, VCPU_ID, KVM_S390_CLEAR_RESET, 0);
>> +	assert_normal();
>> +	assert_initial();
>> +	assert_clear();
>> +	kvm_vm_free(vm);
>> +	return rv;
>> +}
>> +
>> +int main(int argc, char *argv[])
>> +{
>> +	int addl_resets;
>> +
>> +	setbuf(stdout, NULL);	/* Tell stdout not to buffer its content */
>> +	addl_resets = kvm_check_cap(KVM_CAP_S390_VCPU_RESETS);
>> +
>> +	test_initial();
>> +	if (addl_resets) {
> 
> I think you could still fit this into one line, without the need to
> declare the addl_resets variable:

The other question is if we still need to check that if the test is
bundled with the kernel anyway?

> 
> 	if (kvm_check_cap(KVM_CAP_S390_VCPU_RESETS)) {
> 
>> +		test_normal();
>> +		test_clear();
>> +	}
>> +	return 0;
>> +}
> 
> Apart from the nits, this looks pretty good already, thanks for putting
> it together!
> 
>  Thomas
> 



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