Re: [PATCH v3 2/3] selftests: kvm: s390: Add uc_skey VM test case

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

On 9/13/24 1:52 PM, Christoph Schlameuss wrote:
> Add a test case manipulating s390 storage keys from within the ucontrol
> VM.
> 
> Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>

Except for the two nits:
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>


I'll think about what to do with the nits next week.

> ---
>   .../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 084cea02c2fa..f6e3a68f89a9 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;
> @@ -299,8 +326,9 @@ static void uc_handle_exit_ucontrol(FIXTURE_DATA(uc_kvm) * self)
>   }
>   
>   /* verify SIEIC exit
> - * * reset stop requests

Argh, that made it in the patches that I've picked up.

> + * * 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)
>   {
> @@ -317,6 +345,10 @@ 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);
> @@ -473,4 +505,59 @@ 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(true, uc_handle_exit(self));
> +	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*/

Missing space before "*"

> +	ASSERT_EQ(skeyvalue & 0xfa, sync_regs->gprs[1]);
> +	ASSERT_EQ(0x00, sync_regs->gprs[1] & 0x04);
> +	uc_assert_diag44(self);
> +}
> +
>   TEST_HARNESS_MAIN