Re: [PATCH v2 2/3] selftests: kvm: s390: Add uc_skey VM test case

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Mon,  2 Sep 2024 13:50:01 +0200
Christoph Schlameuss <schlameuss@linux.ibm.com> wrote:

> Add a test case manipulating s390 storage keys from within the ucontrol
> VM.
> 
> Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
> ---
>  .../selftests/kvm/s390x/ucontrol_test.c       | 89 ++++++++++++++++++-
>  1 file changed, 88 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/kvm/s390x/ucontrol_test.c b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
> index 04a0d55af617..331a4109b953 100644
> --- a/tools/testing/selftests/kvm/s390x/ucontrol_test.c
> +++ b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
> @@ -79,6 +79,33 @@ asm("test_mem_asm:\n"
>  	"	j	0b\n"
>  );
>  
> +/* Test program manipulating storage keys */
> +extern char test_skey_asm[];
> +asm("test_skey_asm:\n"
> +	"xgr	%r0, %r0\n"
> +
> +	"0:\n"
> +	"	ahi	%r0,1\n"
> +	"	st	%r1,0(%r5,%r6)\n"
> +
> +	"	iske	%r1,%r6\n"
> +	"	ahi	%r0,1\n"
> +	"	diag	0,0,0x44\n"
> +
> +	"	sske	%r1,%r6\n"
> +	"	xgr	%r1,%r1\n"
> +	"	iske	%r1,%r6\n"
> +	"	ahi	%r0,1\n"
> +	"	diag	0,0,0x44\n"
> +
> +	"	rrbe	%r1,%r6\n"
> +	"	iske	%r1,%r6\n"
> +	"	ahi	%r0,1\n"
> +	"	diag	0,0,0x44\n"
> +
> +	"	j	0b\n"
> +);
> +
>  FIXTURE(uc_kvm)
>  {
>  	struct kvm_s390_sie_block *sie_block;
> @@ -275,8 +302,9 @@ static void uc_handle_exit_ucontrol(FIXTURE_DATA(uc_kvm) * self)
>  }
>  
>  /* verify SIEIC exit
> - * * reset stop requests
> + * * handle expected interception codes
>   * * fail on codes not expected in the test cases
> + * Returns if interception is handled / execution can be continued
>   */
>  static bool uc_handle_sieic(FIXTURE_DATA(uc_kvm) * self)
>  {
> @@ -293,6 +321,10 @@ static bool uc_handle_sieic(FIXTURE_DATA(uc_kvm) * self)
>  		/* end execution in caller on intercepted instruction */
>  		pr_info("sie instruction interception\n");
>  		return false;
> +	case ICPT_KSS:
> +		/* disable KSS and continue; KVM would init the skeys here */
> +		sie_block->cpuflags &= ~CPUSTAT_KSS;
> +		return true;
>  	case ICPT_OPEREXC:
>  		/* operation exception */
>  		TEST_FAIL("sie exception on %.4x%.8x", sie_block->ipa, sie_block->ipb);
> @@ -449,4 +481,59 @@ TEST_F(uc_kvm, uc_gprs)
>  	ASSERT_EQ(1, sync_regs->gprs[0]);
>  }
>  
> +TEST_F(uc_kvm, uc_skey)
> +{
> +	u64 test_vaddr = VM_MEM_SIZE - (SZ_1M / 2);
> +	struct kvm_sync_regs *sync_regs = &self->run->s.regs;
> +	struct kvm_run *run = self->run;
> +	u8 skeyvalue = 0x34;
> +
> +	/* copy test_skey_asm to code_hva / code_gpa */
> +	TH_LOG("copy code %p to vm mapped memory %p / %p",
> +	       &test_skey_asm, (void *)self->code_hva, (void *)self->code_gpa);
> +	memcpy((void *)self->code_hva, &test_skey_asm, PAGE_SIZE);
> +
> +	/* set register content for test_skey_asm to access not mapped memory */
> +	sync_regs->gprs[1] = skeyvalue;
> +	sync_regs->gprs[5] = self->base_gpa;
> +	sync_regs->gprs[6] = test_vaddr;
> +	run->kvm_dirty_regs |= KVM_SYNC_GPRS;
> +
> +	/* DAT disabled + 64 bit mode */
> +	run->psw_mask = 0x0000000180000000ULL;
> +	run->psw_addr = self->code_gpa;
> +
> +	ASSERT_EQ(0, uc_run_once(self));
> +	ASSERT_EQ(false, uc_handle_exit(self));

this should be true, since KSS will be triggered

> +	ASSERT_EQ(1, sync_regs->gprs[0]);
> +
> +	/* ISKE */
> +	ASSERT_EQ(0, uc_run_once(self));
> +	ASSERT_EQ(false, uc_handle_exit(self));
> +	ASSERT_EQ(2, sync_regs->gprs[0]);
> +	/* assert initial skey (ACC = 0, R & C = 1) */
> +	ASSERT_EQ(0x06, sync_regs->gprs[1]);
> +	uc_assert_diag44(self);
> +
> +	/* SSKE */
> +	sync_regs->gprs[1] = skeyvalue;
> +	run->kvm_dirty_regs |= KVM_SYNC_GPRS;
> +	ASSERT_EQ(0, uc_run_once(self));
> +	ASSERT_EQ(false, uc_handle_exit(self));
> +	ASSERT_EQ(3, sync_regs->gprs[0]);
> +	ASSERT_EQ(skeyvalue, sync_regs->gprs[1]);
> +	uc_assert_diag44(self);
> +
> +	/* RRBE */
> +	sync_regs->gprs[1] = skeyvalue;
> +	run->kvm_dirty_regs |= KVM_SYNC_GPRS;
> +	ASSERT_EQ(0, uc_run_once(self));
> +	ASSERT_EQ(false, uc_handle_exit(self));
> +	ASSERT_EQ(4, sync_regs->gprs[0]);
> +	/* assert R reset but rest of skey unchanged*/
> +	ASSERT_EQ(skeyvalue & 0xfa, sync_regs->gprs[1]);
> +	ASSERT_EQ(0x00, sync_regs->gprs[1] & 0x04);
> +	uc_assert_diag44(self);
> +}
> +
>  TEST_HARNESS_MAIN