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

[Christoph Schlameuss <schlameuss@linux.ibm.com>]

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));
+	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
-- 
2.46.0