[kvm-unit-tests PATCH v4 0/1] s390x: add migration test for storage keys

[kvm-unit-tests PATCH v4 0/1] s390x: add migration test for storage keys

[Nico Boehr]

v3->v4:
----
* remove useless goto (Thanks Thomas)

v2->v3:
----
* remove some useless variables, style suggestions, improve commit description
  (thanks Janis)
* reverse christmas tree (thanks Claudio)

v1->v2:
----
* As per discussion with Janis and Claudio, remove the actual access check from
  the test. This also allows us to remove the check_pgm_int_code_xfail() patch.
* Typos/Style suggestions (thanks Janis)

Upon migration, we expect storage keys set by the guest to be preserved,
so add a test for it.

We keep 128 pages and set predictable storage keys. Then, we migrate and check
they can be read back.

Nico Boehr (1):
  s390x: add migration test for storage keys

 s390x/Makefile         |  1 +
 s390x/migration-skey.c | 73 ++++++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg    |  4 +++
 3 files changed, 78 insertions(+)
 create mode 100644 s390x/migration-skey.c

-- 
2.36.1

[kvm-unit-tests PATCH v4 1/1] s390x: add migration test for storage keys

[Nico Boehr]

Upon migration, we expect storage keys set by the guest to be preserved, so add
a test for it.

We keep 128 pages and set predictable storage keys. Then, we migrate and check
that they can be read back and match the value originally set.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
---
 s390x/Makefile         |  1 +
 s390x/migration-skey.c | 73 ++++++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg    |  4 +++
 3 files changed, 78 insertions(+)
 create mode 100644 s390x/migration-skey.c

diff --git a/s390x/Makefile b/s390x/Makefile
index 25802428fa13..94fc5c1a3527 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -33,6 +33,7 @@ tests += $(TEST_DIR)/adtl-status.elf
 tests += $(TEST_DIR)/migration.elf
 tests += $(TEST_DIR)/pv-attest.elf
 tests += $(TEST_DIR)/migration-cmm.elf
+tests += $(TEST_DIR)/migration-skey.elf
 
 pv-tests += $(TEST_DIR)/pv-diags.elf
 
diff --git a/s390x/migration-skey.c b/s390x/migration-skey.c
new file mode 100644
index 000000000000..323aa83202bb
--- /dev/null
+++ b/s390x/migration-skey.c
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Storage Key migration tests
+ *
+ * Copyright IBM Corp. 2022
+ *
+ * Authors:
+ *  Nico Boehr <nrb@linux.ibm.com>
+ */
+
+#include <libcflat.h>
+#include <asm/facility.h>
+#include <asm/page.h>
+#include <asm/mem.h>
+#include <asm/interrupt.h>
+#include <hardware.h>
+
+#define NUM_PAGES 128
+static uint8_t pagebuf[NUM_PAGES][PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+
+static void test_migration(void)
+{
+	union skey expected_key, actual_key;
+	int i, key_to_set;
+
+	for (i = 0; i < NUM_PAGES; i++) {
+		/*
+		 * Storage keys are 7 bit, lowest bit is always returned as zero
+		 * by iske
+		 */
+		key_to_set = i * 2;
+		set_storage_key(pagebuf[i], key_to_set, 1);
+	}
+
+	puts("Please migrate me, then press return\n");
+	(void)getchar();
+
+	for (i = 0; i < NUM_PAGES; i++) {
+		report_prefix_pushf("page %d", i);
+
+		actual_key.val = get_storage_key(pagebuf[i]);
+		expected_key.val = i * 2;
+
+		/* ignore reference bit */
+		actual_key.str.rf = 0;
+		expected_key.str.rf = 0;
+
+		report(actual_key.val == expected_key.val, "expected_key=0x%x actual_key=0x%x", expected_key.val, actual_key.val);
+
+		report_prefix_pop();
+	}
+}
+
+int main(void)
+{
+	report_prefix_push("migration-skey");
+	if (test_facility(169)) {
+		report_skip("storage key removal facility is active");
+
+		/*
+		 * If we just exit and don't ask migrate_cmd to migrate us, it
+		 * will just hang forever. Hence, also ask for migration when we
+		 * skip this test altogether.
+		 */
+		puts("Please migrate me, then press return\n");
+		(void)getchar();
+	} else {
+		test_migration();
+	}
+
+	report_prefix_pop();
+	return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index 9b97d0471bcf..8e52f560bb1e 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -180,3 +180,7 @@ smp = 2
 [migration-cmm]
 file = migration-cmm.elf
 groups = migration
+
+[migration-skey]
+file = migration-skey.elf
+groups = migration
-- 
2.36.1

Re: [kvm-unit-tests PATCH v4 0/1] s390x: add migration test for storage keys

[Claudio Imbrenda]

On Wed,  8 Jun 2022 15:13:27 +0200
Nico Boehr <nrb@linux.ibm.com> wrote:

thanks, queued

> v3->v4:
> ----
> * remove useless goto (Thanks Thomas)
> 
> v2->v3:
> ----
> * remove some useless variables, style suggestions, improve commit description
>   (thanks Janis)
> * reverse christmas tree (thanks Claudio)
> 
> v1->v2:
> ----
> * As per discussion with Janis and Claudio, remove the actual access check from
>   the test. This also allows us to remove the check_pgm_int_code_xfail() patch.
> * Typos/Style suggestions (thanks Janis)
> 
> Upon migration, we expect storage keys set by the guest to be preserved,
> so add a test for it.
> 
> We keep 128 pages and set predictable storage keys. Then, we migrate and check
> they can be read back.
> 
> Nico Boehr (1):
>   s390x: add migration test for storage keys
> 
>  s390x/Makefile         |  1 +
>  s390x/migration-skey.c | 73 ++++++++++++++++++++++++++++++++++++++++++
>  s390x/unittests.cfg    |  4 +++
>  3 files changed, 78 insertions(+)
>  create mode 100644 s390x/migration-skey.c
> 

Re: [kvm-unit-tests PATCH v4 1/1] s390x: add migration test for storage keys

[Janosch Frank]

On 6/8/22 15:13, Nico Boehr wrote:
> Upon migration, we expect storage keys set by the guest to be preserved, so add
> a test for it.
> 
> We keep 128 pages and set predictable storage keys. Then, we migrate and check
> that they can be read back and match the value originally set.
> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> ---
>   s390x/Makefile         |  1 +
>   s390x/migration-skey.c | 73 ++++++++++++++++++++++++++++++++++++++++++
>   s390x/unittests.cfg    |  4 +++
>   3 files changed, 78 insertions(+)
>   create mode 100644 s390x/migration-skey.c
> 
> diff --git a/s390x/Makefile b/s390x/Makefile
> index 25802428fa13..94fc5c1a3527 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -33,6 +33,7 @@ tests += $(TEST_DIR)/adtl-status.elf
>   tests += $(TEST_DIR)/migration.elf
>   tests += $(TEST_DIR)/pv-attest.elf
>   tests += $(TEST_DIR)/migration-cmm.elf
> +tests += $(TEST_DIR)/migration-skey.elf
>   
>   pv-tests += $(TEST_DIR)/pv-diags.elf
>   
> diff --git a/s390x/migration-skey.c b/s390x/migration-skey.c
> new file mode 100644
> index 000000000000..323aa83202bb
> --- /dev/null
> +++ b/s390x/migration-skey.c
> @@ -0,0 +1,73 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Storage Key migration tests
> + *
> + * Copyright IBM Corp. 2022
> + *
> + * Authors:
> + *  Nico Boehr <nrb@linux.ibm.com>
> + */
> +
> +#include <libcflat.h>
> +#include <asm/facility.h>
> +#include <asm/page.h>
> +#include <asm/mem.h>
> +#include <asm/interrupt.h>
> +#include <hardware.h>
> +
> +#define NUM_PAGES 128
> +static uint8_t pagebuf[NUM_PAGES][PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
> +
> +static void test_migration(void)
> +{
> +	union skey expected_key, actual_key;
> +	int i, key_to_set;
> +
> +	for (i = 0; i < NUM_PAGES; i++) {
> +		/*
> +		 * Storage keys are 7 bit, lowest bit is always returned as zero
> +		 * by iske
> +		 */

Maybe add:
This loop will set all 7 bits which means we set fetch protection as 
well as reference and change indication for some keys.

> +		key_to_set = i * 2;
> +		set_storage_key(pagebuf[i], key_to_set, 1);
> +	}
> +
> +	puts("Please migrate me, then press return\n");
> +	(void)getchar();
> +
> +	for (i = 0; i < NUM_PAGES; i++) {
> +		report_prefix_pushf("page %d", i);
> +
> +		actual_key.val = get_storage_key(pagebuf[i]);

iske is nice but I think it would also be interesting to check if the 
actual memory protection was carried over. The iske check is enough for 
now though.

> +		expected_key.val = i * 2;
> +
> +		/* ignore reference bit */
> +		actual_key.str.rf = 0;
> +		expected_key.str.rf = 0;
> +
> +		report(actual_key.val == expected_key.val, "expected_key=0x%x actual_key=0x%x", expected_key.val, actual_key.val);

This spams the log with useless information and hence I generally try to 
avoid printing large loops.

Instead we should print all fails or a simple success message if all 
comparisons were successful.

> +
> +		report_prefix_pop();
> +	}
> +}
> +
> +int main(void)
> +{
> +	report_prefix_push("migration-skey");
> +	if (test_facility(169)) {
> +		report_skip("storage key removal facility is active");
> +
> +		/*
> +		 * If we just exit and don't ask migrate_cmd to migrate us, it
> +		 * will just hang forever. Hence, also ask for migration when we
> +		 * skip this test altogether.
> +		 */
> +		puts("Please migrate me, then press return\n");
> +		(void)getchar();
> +	} else {
> +		test_migration();
> +	}
> +
> +	report_prefix_pop();
> +	return report_summary();
> +}
> diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
> index 9b97d0471bcf..8e52f560bb1e 100644
> --- a/s390x/unittests.cfg
> +++ b/s390x/unittests.cfg
> @@ -180,3 +180,7 @@ smp = 2
>   [migration-cmm]
>   file = migration-cmm.elf
>   groups = migration
> +
> +[migration-skey]
> +file = migration-skey.elf
> +groups = migration

Re: [kvm-unit-tests PATCH v4 1/1] s390x: add migration test for storage keys

[Claudio Imbrenda]

On Fri, 10 Jun 2022 10:49:28 +0200
Janosch Frank <frankja@linux.ibm.com> wrote:

[...]

> > +		key_to_set = i * 2;
> > +		set_storage_key(pagebuf[i], key_to_set, 1);
> > +	}
> > +
> > +	puts("Please migrate me, then press return\n");
> > +	(void)getchar();
> > +
> > +	for (i = 0; i < NUM_PAGES; i++) {
> > +		report_prefix_pushf("page %d", i);
> > +
> > +		actual_key.val = get_storage_key(pagebuf[i]);  
> 
> iske is nice but I think it would also be interesting to check if the 
> actual memory protection was carried over. The iske check is enough for 
> now though.

we had that in a previous version, but I think it's overkill, there are
separate tests to check for key protection, I think?

also, under TCG the value of the storage keys is migrated, but there is
no protection, this makes the test unnecessarily complex

[...]

Re: [kvm-unit-tests PATCH v4 1/1] s390x: add migration test for storage keys:q!

[Nico Boehr]

On Fri, 10 Jun 2022 10:49:28 +0200
Janosch Frank <frankja@linux.ibm.com> wrote:

> On 6/8/22 15:13, Nico Boehr wrote:
> > diff --git a/s390x/migration-skey.c b/s390x/migration-skey.c
> > new file mode 100644
> > index 000000000000..323aa83202bb
[...]
> > +static void test_migration(void)
> > +{
> > +	union skey expected_key, actual_key;
> > +	int i, key_to_set;
> > +
> > +	for (i = 0; i < NUM_PAGES; i++) {
> > +		/*
> > +		 * Storage keys are 7 bit, lowest bit is always returned as zero
> > +		 * by iske
> > +		 */  
> 
> Maybe add:
> This loop will set all 7 bits which means we set fetch protection as 
> well as reference and change indication for some keys.

OK, done.

> 
> > +		key_to_set = i * 2;
> > +		set_storage_key(pagebuf[i], key_to_set, 1);
> > +	}
> > +
> > +	puts("Please migrate me, then press return\n");
> > +	(void)getchar();
> > +
> > +	for (i = 0; i < NUM_PAGES; i++) {
> > +		report_prefix_pushf("page %d", i);
> > +
> > +		actual_key.val = get_storage_key(pagebuf[i]);  
> 
> iske is nice but I think it would also be interesting to check if the 
> actual memory protection was carried over. The iske check is enough for 
> now though.

OK, we can add an access check later on if we think it's needed.

> 
> > +		expected_key.val = i * 2;
> > +
> > +		/* ignore reference bit */
> > +		actual_key.str.rf = 0;
> > +		expected_key.str.rf = 0;
> > +
> > +		report(actual_key.val == expected_key.val, "expected_key=0x%x actual_key=0x%x", expected_key.val, actual_key.val);  
> 
> This spams the log with useless information and hence I generally try to 
> avoid printing large loops.
> 
> Instead we should print all fails or a simple success message if all 
> comparisons were successful.

OK will be in the next version.