[kvm-unit-tests PATCH v5 0/4] s390x: SCLP Unit test

[kvm-unit-tests PATCH v5 0/4] s390x: SCLP Unit test

[Claudio Imbrenda]

This patchset contains some minor cleanup, some preparatory work and
then the SCLP unit test itself.

The unit test checks the following:
    
    * Correctly ignoring instruction bits that should be ignored
    * Privileged instruction check
    * Check for addressing exceptions
    * Specification exceptions:
      - SCCB size less than 8
      - SCCB unaligned
      - SCCB overlaps prefix or lowcore
      - SCCB address higher than 2GB
    * Return codes for
      - Invalid command
      - SCCB too short (but at least 8)
      - SCCB page boundary violation

v4 -> v5
* updated usage of report()
* added SPX and STPX wrappers to the library
* improved readability
* addressed some more comments
v3 -> v4
* export sclp_setup_int instead of copying it
* add more comments
* rename some more variables to improve readability
* improve the prefix test
* improved the invalid address test
* addressed further comments received during review
v2 -> v3
* generally improved the naming of variables
* added and fixed comments
* renamed test_one_run to test_one_simple
* added some const where needed
* addresed many more small comments received during review
v1 -> v2
* fix many small issues that came up during the first round of reviews
* add comments to each function
* use a static buffer for the SCCP template when used

Claudio Imbrenda (4):
  s390x: export sclp_setup_int
  s390x: sclp: add service call instruction wrapper
  s390x: lib: add SPX and STPX instruction wrapper
  s390x: SCLP unit test

 s390x/Makefile           |   1 +
 lib/s390x/asm/arch_def.h |  26 +++
 lib/s390x/sclp.h         |   1 +
 lib/s390x/sclp.c         |   9 +-
 s390x/sclp.c             | 462 +++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg      |   8 +
 6 files changed, 500 insertions(+), 7 deletions(-)
 create mode 100644 s390x/sclp.c

-- 
2.24.1

[kvm-unit-tests PATCH v5 1/4] s390x: export sclp_setup_int

[Claudio Imbrenda]

Export sclp_setup_int() so that it can be used in tests.

Needed for an upcoming unit test.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
---
 lib/s390x/sclp.h | 1 +
 lib/s390x/sclp.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h
index 6d40fb7..675f07e 100644
--- a/lib/s390x/sclp.h
+++ b/lib/s390x/sclp.h
@@ -265,6 +265,7 @@ typedef struct ReadEventData {
 } __attribute__((packed)) ReadEventData;
 
 extern char _sccb[];
+void sclp_setup_int(void);
 void sclp_handle_ext(void);
 void sclp_wait_busy(void);
 void sclp_mark_busy(void);
diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
index 7798f04..123b639 100644
--- a/lib/s390x/sclp.c
+++ b/lib/s390x/sclp.c
@@ -45,7 +45,7 @@ static void mem_init(phys_addr_t mem_end)
 	page_alloc_ops_enable();
 }
 
-static void sclp_setup_int(void)
+void sclp_setup_int(void)
 {
 	uint64_t mask;
 
-- 
2.24.1

[kvm-unit-tests PATCH v5 2/4] s390x: sclp: add service call instruction wrapper

[Claudio Imbrenda]

Add a wrapper for the service call instruction, and use it for SCLP
interactions instead of using inline assembly everywhere.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
---
 lib/s390x/asm/arch_def.h | 13 +++++++++++++
 lib/s390x/sclp.c         |  7 +------
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index cf6e1ca..1a5e3c6 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -271,4 +271,17 @@ static inline int stsi(void *addr, int fc, int sel1, int sel2)
 	return cc;
 }
 
+static inline int servc(uint32_t command, unsigned long sccb)
+{
+	int cc;
+
+	asm volatile(
+		"       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
+		"       ipm     %0\n"
+		"       srl     %0,28"
+		: "=&d" (cc) : "d" (command), "a" (sccb)
+		: "cc", "memory");
+	return cc;
+}
+
 #endif
diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
index 123b639..4054d0e 100644
--- a/lib/s390x/sclp.c
+++ b/lib/s390x/sclp.c
@@ -116,12 +116,7 @@ int sclp_service_call(unsigned int command, void *sccb)
 	int cc;
 
 	sclp_setup_int();
-	asm volatile(
-		"       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
-		"       ipm     %0\n"
-		"       srl     %0,28"
-		: "=&d" (cc) : "d" (command), "a" (__pa(sccb))
-		: "cc", "memory");
+	cc = servc(command, __pa(sccb));
 	sclp_wait_busy();
 	if (cc == 3)
 		return -1;
-- 
2.24.1

[kvm-unit-tests PATCH v5 3/4] s390x: lib: add SPX and STPX instruction wrapper

[Claudio Imbrenda]

Add a wrapper for the SET PREFIX and STORE PREFIX instructions, and
use it instead of using inline assembly everywhere.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 lib/s390x/asm/arch_def.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 1a5e3c6..38c9dfa 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -284,4 +284,17 @@ static inline int servc(uint32_t command, unsigned long sccb)
 	return cc;
 }
 
+static inline void spx(uint32_t new_prefix)
+{
+	asm volatile("spx %0" : : "Q" (new_prefix) : "memory");
+}
+
+static inline uint32_t stpx(void)
+{
+	uint32_t prefix;
+
+	asm volatile("stpx %0" : "=Q" (prefix));
+	return prefix;
+}
+
 #endif
-- 
2.24.1

Re: [kvm-unit-tests PATCH v5 3/4] s390x: lib: add SPX and STPX instruction wrapper

[Thomas Huth]

On 08/01/2020 17.13, Claudio Imbrenda wrote:
> Add a wrapper for the SET PREFIX and STORE PREFIX instructions, and
> use it instead of using inline assembly everywhere.

Either some hunks are missing in this patch, or you should update the
patch description and remove the second part of the sentence ? ... at
least I did not spot the changes where you "use it instead of using
inline assembly everywhere".

 Thomas


> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>  lib/s390x/asm/arch_def.h | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index 1a5e3c6..38c9dfa 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -284,4 +284,17 @@ static inline int servc(uint32_t command, unsigned long sccb)
>  	return cc;
>  }
>  
> +static inline void spx(uint32_t new_prefix)
> +{
> +	asm volatile("spx %0" : : "Q" (new_prefix) : "memory");
> +}
> +
> +static inline uint32_t stpx(void)
> +{
> +	uint32_t prefix;
> +
> +	asm volatile("stpx %0" : "=Q" (prefix));
> +	return prefix;
> +}
> +
>  #endif
> 

Re: [kvm-unit-tests PATCH v5 3/4] s390x: lib: add SPX and STPX instruction wrapper

[Claudio Imbrenda]

On Wed, 8 Jan 2020 19:58:27 +0100
Thomas Huth <thuth@redhat.com> wrote:

> On 08/01/2020 17.13, Claudio Imbrenda wrote:
> > Add a wrapper for the SET PREFIX and STORE PREFIX instructions, and
> > use it instead of using inline assembly everywhere.  
> 
> Either some hunks are missing in this patch, or you should update the
> patch description and remove the second part of the sentence ? ... at
> least I did not spot the changes where you "use it instead of using
> inline assembly everywhere".


oops sorry, the description is a little misleading. I meant
everywhere in the specific unit test, not everywhere in the whole
source tree. 

I should either change the description or actually patch the remaining
users of inline assembly to use the wrappers instead. (any preference?)

Re: [kvm-unit-tests PATCH v5 3/4] s390x: lib: add SPX and STPX instruction wrapper

[Thomas Huth]

On 09/01/2020 12.36, Claudio Imbrenda wrote:
> On Wed, 8 Jan 2020 19:58:27 +0100
> Thomas Huth <thuth@redhat.com> wrote:
> 
>> On 08/01/2020 17.13, Claudio Imbrenda wrote:
>>> Add a wrapper for the SET PREFIX and STORE PREFIX instructions, and
>>> use it instead of using inline assembly everywhere.  
>>
>> Either some hunks are missing in this patch, or you should update the
>> patch description and remove the second part of the sentence ? ... at
>> least I did not spot the changes where you "use it instead of using
>> inline assembly everywhere".
> 
> 
> oops sorry, the description is a little misleading. I meant
> everywhere in the specific unit test, not everywhere in the whole
> source tree. 
> 
> I should either change the description or actually patch the remaining
> users of inline assembly to use the wrappers instead. (any preference?)

No preferences from my side. If you don't want/have to respin, the patch
description could be fixed when picking up the patch, otherwise simply
do whatever you prefer in v6.

 Thomas

[kvm-unit-tests PATCH v5 4/4] s390x: SCLP unit test

[Claudio Imbrenda]

SCLP unit test. Testing the following:

* Correctly ignoring instruction bits that should be ignored
* Privileged instruction check
* Check for addressing exceptions
* Specification exceptions:
  - SCCB size less than 8
  - SCCB unaligned
  - SCCB overlaps prefix or lowcore
  - SCCB address higher than 2GB
* Return codes for
  - Invalid command
  - SCCB too short (but at least 8)
  - SCCB page boundary violation

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 s390x/Makefile      |   1 +
 s390x/sclp.c        | 462 ++++++++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg |   8 +
 3 files changed, 471 insertions(+)
 create mode 100644 s390x/sclp.c

diff --git a/s390x/Makefile b/s390x/Makefile
index 3744372..ddb4b48 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -16,6 +16,7 @@ tests += $(TEST_DIR)/diag288.elf
 tests += $(TEST_DIR)/stsi.elf
 tests += $(TEST_DIR)/skrf.elf
 tests += $(TEST_DIR)/smp.elf
+tests += $(TEST_DIR)/sclp.elf
 tests_binary = $(patsubst %.elf,%.bin,$(tests))
 
 all: directories test_cases test_cases_binary
diff --git a/s390x/sclp.c b/s390x/sclp.c
new file mode 100644
index 0000000..7aefdc8
--- /dev/null
+++ b/s390x/sclp.c
@@ -0,0 +1,462 @@
+/*
+ * Service Call tests
+ *
+ * Copyright (c) 2019 IBM Corp
+ *
+ * Authors:
+ *  Claudio Imbrenda <imbrenda@linux.ibm.com>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#include <libcflat.h>
+#include <asm/page.h>
+#include <asm/asm-offsets.h>
+#include <asm/interrupt.h>
+#include <sclp.h>
+
+#define PGM_NONE	1
+#define PGM_BIT_SPEC	(1ULL << PGM_INT_CODE_SPECIFICATION)
+#define PGM_BIT_ADDR	(1ULL << PGM_INT_CODE_ADDRESSING)
+#define PGM_BIT_PRIV	(1ULL << PGM_INT_CODE_PRIVILEGED_OPERATION)
+#define MKPTR(x) ((void *)(uint64_t)(x))
+
+#define LC_SIZE (2 * PAGE_SIZE)
+
+static uint8_t pagebuf[LC_SIZE] __attribute__((aligned(LC_SIZE)));	/* scratch pages used for some tests */
+static uint8_t prefix_buf[LC_SIZE] __attribute__((aligned(LC_SIZE)));	/* temporary lowcore for test_sccb_prefix */
+static uint8_t sccb_template[PAGE_SIZE];				/* SCCB template to be used */
+static uint32_t valid_code;						/* valid command code for READ SCP INFO */
+static struct lowcore *lc;
+
+/**
+ * Perform one service call, handling exceptions and interrupts.
+ */
+static int sclp_service_call_test(unsigned int command, void *sccb)
+{
+	int cc;
+
+	sclp_mark_busy();
+	sclp_setup_int();
+	cc = servc(command, __pa(sccb));
+	if (lc->pgm_int_code) {
+		sclp_handle_ext();
+		return 0;
+	}
+	if (!cc)
+		sclp_wait_busy();
+	return cc;
+}
+
+/**
+ * Perform one test at the given address, optionally using the SCCB template,
+ * checking for the expected program interrupts and return codes.
+ *
+ * The parameter buf_len indicates the number of bytes of the template that
+ * should be copied to the test address, and should be 0 when the test
+ * address is invalid, in which case nothing is copied.
+ *
+ * The template is used to simplify tests where the same buffer content is
+ * used many times in a row, at different addresses.
+ *
+ * Returns true in case of success or false in case of failure
+ */
+static bool test_one_sccb(uint32_t cmd, uint8_t *addr, uint16_t buf_len, uint64_t exp_pgm, uint16_t exp_rc)
+{
+	SCCBHeader *h = (SCCBHeader *)addr;
+	int res, pgm;
+
+	/* Copy the template to the test address if needed */
+	if (buf_len)
+		memcpy(addr, sccb_template, buf_len);
+	expect_pgm_int();
+	/* perform the actual call */
+	res = sclp_service_call_test(cmd, h);
+	if (res) {
+		report_info("SCLP not ready (command %#x, address %p, cc %d)", cmd, addr, res);
+		return false;
+	}
+	pgm = clear_pgm_int();
+	/* Check if the program exception was one of the expected ones */
+	if (!((1ULL << pgm) & exp_pgm)) {
+		report_info("First failure at addr %p, buf_len %d, cmd %#x, pgm code %d",
+				addr, buf_len, cmd, pgm);
+		return false;
+	}
+	/* Check if the response code is the one expected */
+	if (exp_rc && exp_rc != h->response_code) {
+		report_info("First failure at addr %p, buf_len %d, cmd %#x, resp code %#x",
+				addr, buf_len, cmd, h->response_code);
+		return false;
+	}
+	return true;
+}
+
+/**
+ * Wrapper for test_one_sccb to set up a simple SCCB template.
+ *
+ * The parameter sccb_len indicates the value that will be saved in the SCCB
+ * length field of the SCCB, buf_len indicates the number of bytes of
+ * template that need to be copied to the actual test address. In many cases
+ * it's enough to clear/copy the first 8 bytes of the buffer, while the SCCB
+ * itself can be larger.
+ *
+ * Returns true in case of success or false in case of failure
+ */
+static bool test_one_simple(uint32_t cmd, uint8_t *addr, uint16_t sccb_len,
+			uint16_t buf_len, uint64_t exp_pgm, uint16_t exp_rc)
+{
+	memset(sccb_template, 0, sizeof(sccb_template));
+	((SCCBHeader *)sccb_template)->length = sccb_len;
+	return test_one_sccb(cmd, addr, buf_len, exp_pgm, exp_rc);
+}
+
+/**
+ * Test SCCB lengths < 8.
+ */
+static void test_sccb_too_short(void)
+{
+	int len;
+
+	for (len = 0; len < 8; len++)
+		if (!test_one_simple(valid_code, pagebuf, len, 8, PGM_BIT_SPEC, 0))
+			break;
+
+	report(len == 8, "SCCB too short");
+}
+
+/**
+ * Test SCCBs that are not 64-bit aligned.
+ */
+static void test_sccb_unaligned(void)
+{
+	int offset;
+
+	for (offset = 1; offset < 8; offset++)
+		if (!test_one_simple(valid_code, offset + pagebuf, 8, 8, PGM_BIT_SPEC, 0))
+			break;
+	report(offset == 8, "SCCB unaligned");
+}
+
+/**
+ * Test SCCBs whose address is in the lowcore or prefix area.
+ */
+static void test_sccb_prefix(void)
+{
+	uint8_t scratch[2 * PAGE_SIZE];
+	uint32_t prefix, new_prefix;
+	int offset;
+
+	/*
+	 * copy the current lowcore to the future new location, otherwise we
+	 * will not have a valid lowcore after setting the new prefix.
+	 */
+	memcpy(prefix_buf, 0, 2 * PAGE_SIZE);
+	/* save the current prefix (it's probably going to be 0) */
+	prefix = stpx();
+	/*
+	 * save the current content of absolute pages 0 and 1, so we can
+	 * restore them after we trash them later on
+	 */
+	memcpy(scratch, (void *)(intptr_t)prefix, 2 * PAGE_SIZE);
+	/* set the new prefix to prefix_buf */
+	new_prefix = (uint32_t)(intptr_t)prefix_buf;
+	spx(new_prefix);
+
+	/*
+	 * testing with SCCB addresses in the lowcore; since we can't
+	 * actually trash the lowcore (unsurprisingly, things break if we
+	 * do), this will be a read-only test.
+	 */
+	for (offset = 0; offset < 2 * PAGE_SIZE; offset += 8)
+		if (!test_one_sccb(valid_code, MKPTR(offset), 0, PGM_BIT_SPEC, 0))
+			break;
+	report(offset == 2 * PAGE_SIZE, "SCCB low pages");
+
+	/*
+	 * this will trash the contents of the two pages at absolute
+	 * address 0; we will need to restore them later.
+	 */
+	for (offset = 0; offset < 2 * PAGE_SIZE; offset += 8)
+		if (!test_one_simple(valid_code, MKPTR(new_prefix + offset), 8, 8, PGM_BIT_SPEC, 0))
+			break;
+	report(offset == 2 * PAGE_SIZE, "SCCB prefix pages");
+
+	/* restore the previous contents of absolute pages 0 and 1 */
+	memcpy(prefix_buf, 0, 2 * PAGE_SIZE);
+	/* restore the prefix to the original value */
+	spx(prefix);
+}
+
+/**
+ * Test SCCBs that are above 2GB. If outside of memory, an addressing
+ * exception is also allowed.
+ */
+static void test_sccb_high(void)
+{
+	SCCBHeader *h = (SCCBHeader *)pagebuf;
+	uintptr_t a[33 * 4 * 2 + 2];	/* for the list of addresses to test */
+
+	uint64_t maxram;
+	int i, pgm, len = 0;
+
+	h->length = 8;
+	/* addresses with 1 bit set in the first 33 bits */
+	for (i = 0; i < 33; i++)
+		a[len++] = 1UL << (i + 31);
+	/* addresses with 2 consecutive bits set in the first 33 bits */
+	for (i = 0; i < 33; i++)
+		a[len++] = 3UL << (i + 31);
+	/* addresses with all bits set in bits 0..N */
+	for (i = 0; i < 33; i++)
+		a[len++] = 0xffffffff80000000UL << i;
+	/* addresses with all bits set in bits N..33 */
+	a[len++] = 0x80000000;
+	for (i = 1; i < 33; i++, len++)
+		a[len] = a[len - 1] | (1UL << (i + 31));
+	/* all the addresses above, but adding the offset of a valid buffer */
+	for (i = 0; i < len; i++)
+		a[len + i] = a[i] + (intptr_t)h;
+	len += i;
+	/* two more hand-crafted addresses */
+	a[len++] = 0xdeadbeef00000000;
+	a[len++] = 0xdeaddeadbeef0000;
+
+	maxram = get_ram_size();
+	for (i = 0; i < len; i++) {
+		pgm = PGM_BIT_SPEC | (a[i] >= maxram ? PGM_BIT_ADDR : 0);
+		if (!test_one_sccb(valid_code, (void *)a[i], 0, pgm, 0))
+			break;
+	}
+	report(i == len, "SCCB high addresses");
+}
+
+/**
+ * Test invalid commands, both invalid command detail codes and valid
+ * ones with invalid command class code.
+ */
+static void test_inval(void)
+{
+	const uint16_t res = SCLP_RC_INVALID_SCLP_COMMAND;
+	uint32_t cmd;
+	int i;
+
+	report_prefix_push("Invalid command");
+	for (i = 0; i < 65536; i++) {
+		cmd = 0xdead0000 | i;
+		if (!test_one_simple(cmd, pagebuf, PAGE_SIZE, PAGE_SIZE, PGM_NONE, res))
+			break;
+	}
+	report(i == 65536, "Command detail code");
+
+	for (i = 0; i < 256; i++) {
+		cmd = (valid_code & ~0xff) | i;
+		if (cmd == valid_code)
+			continue;
+		if (!test_one_simple(cmd, pagebuf, PAGE_SIZE, PAGE_SIZE, PGM_NONE, res))
+			break;
+	}
+	report(i == 256, "Command class code");
+	report_prefix_pop();
+}
+
+
+/**
+ * Test short SCCBs (but larger than 8).
+ */
+static void test_short(void)
+{
+	const uint16_t res = SCLP_RC_INSUFFICIENT_SCCB_LENGTH;
+	int len;
+
+	for (len = 8; len < 144; len++)
+		if (!test_one_simple(valid_code, pagebuf, len, len, PGM_NONE, res))
+			break;
+	report(len == 144, "Insufficient SCCB length (Read SCP info)");
+
+	for (len = 8; len < 40; len++)
+		if (!test_one_simple(SCLP_READ_CPU_INFO, pagebuf, len, len, PGM_NONE, res))
+			break;
+	report(len == 40, "Insufficient SCCB length (Read CPU info)");
+}
+
+/**
+ * Test SCCB page boundary violations.
+ */
+static void test_boundary(void)
+{
+	const uint32_t cmd = SCLP_CMD_WRITE_EVENT_DATA;
+	const uint16_t res = SCLP_RC_SCCB_BOUNDARY_VIOLATION;
+	WriteEventData *sccb = (WriteEventData *)sccb_template;
+	int len, offset;
+
+	memset(sccb_template, 0, sizeof(sccb_template));
+	sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
+	for (len = 32; len <= 4096; len++) {
+		offset = len & 7 ? len & ~7 : len - 8;
+		for (offset = 4096 - offset; offset < 4096; offset += 8) {
+			sccb->h.length = len;
+			if (!test_one_sccb(cmd, offset + pagebuf, len, PGM_NONE, res))
+				goto out;
+		}
+	}
+out:
+	report(len > 4096 && offset == 4096, "SCCB page boundary violation");
+}
+
+/**
+ * Test excessively long SCCBs.
+ */
+static void test_toolong(void)
+{
+	const uint32_t cmd = SCLP_CMD_WRITE_EVENT_DATA;
+	const uint16_t res = SCLP_RC_SCCB_BOUNDARY_VIOLATION;
+	WriteEventData *sccb = (WriteEventData *)sccb_template;
+	int len;
+
+	memset(sccb_template, 0, sizeof(sccb_template));
+	sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
+	for (len = 4097; len < 8192; len++) {
+		sccb->h.length = len;
+		if (!test_one_sccb(cmd, pagebuf, PAGE_SIZE, PGM_NONE, res))
+			break;
+	}
+	report(len == 8192, "SCCB bigger than 4k");
+}
+
+/**
+ * Test privileged operation.
+ */
+static void test_priv(void)
+{
+	SCCBHeader *h = (SCCBHeader *)pagebuf;
+
+	report_prefix_push("Privileged operation");
+	h->length = 8;
+	expect_pgm_int();
+	enter_pstate();
+	servc(valid_code, __pa(h));
+	check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
+	report_prefix_pop();
+}
+
+/**
+ * Test addressing exceptions. We need to test SCCB addresses between the
+ * end of available memory and 2GB, because after 2GB a specification
+ * exception is also allowed.
+ * Only applicable if the VM has less than 2GB of memory
+ */
+static void test_addressing(void)
+{
+	unsigned long i, maxram = get_ram_size();
+
+	/* the VM has more than 2GB of memory */
+	if (maxram >= 0x80000000) {
+		report_skip("Invalid SCCB address");
+		return;
+	}
+	/* test all possible valid addresses immediately after the end of memory
+	 * up to 64KB after the end of memory
+	 */
+	for (i = 0; i < 0x10000 && i + maxram < 0x80000000; i += 8)
+		if (!test_one_sccb(valid_code, MKPTR(i + maxram), 0, PGM_BIT_ADDR, 0))
+			goto out;
+	/* test more addresses until we reach 1MB after end of memory;
+	 * increment by a prime number (times 8) in order to test all
+	 * possible valid offsets inside pages
+	 */
+	for (; i < 0x100000 && i + maxram < 0x80000000 ; i += 808)
+		if (!test_one_sccb(valid_code, MKPTR(i + maxram), 0, PGM_BIT_ADDR, 0))
+			goto out;
+	/* test the remaining addresses until we reach address 2GB;
+	 * increment by a prime number (times 8) in order to test all
+	 * possible valid offsets inside pages
+	 */
+	for (; i < 0x80000000; i += 800024)
+		if (!test_one_sccb(valid_code, MKPTR(i + maxram), 0, PGM_BIT_ADDR, 0))
+			goto out;
+out:
+	report(i >= 0x80000000, "Invalid SCCB address");
+}
+
+/**
+ * Test some bits in the instruction format that are specified to be ignored.
+ */
+static void test_instbits(void)
+{
+	SCCBHeader *h = (SCCBHeader *)pagebuf;
+	int cc;
+
+	expect_pgm_int();
+	sclp_mark_busy();
+	h->length = 8;
+	sclp_setup_int();
+
+	asm volatile(
+		"       .insn   rre,0xb2204200,%1,%2\n"  /* servc %1,%2 */
+		"       ipm     %0\n"
+		"       srl     %0,28"
+		: "=&d" (cc) : "d" (valid_code), "a" (__pa(pagebuf))
+		: "cc", "memory");
+	if (lc->pgm_int_code) {
+		sclp_handle_ext();
+		cc = 1;
+	} else if (!cc)
+		sclp_wait_busy();
+	report(cc == 0, "Instruction format ignored bits");
+}
+
+/**
+ * Find a valid READ INFO command code; not all codes are always allowed, and
+ * probing should be performed in the right order.
+ */
+static void find_valid_sclp_code(void)
+{
+	const unsigned int commands[] = { SCLP_CMDW_READ_SCP_INFO_FORCED,
+					  SCLP_CMDW_READ_SCP_INFO };
+	SCCBHeader *h = (SCCBHeader *)pagebuf;
+	int i, cc;
+
+	for (i = 0; i < ARRAY_SIZE(commands); i++) {
+		sclp_mark_busy();
+		memset(h, 0, sizeof(*h));
+		h->length = 4096;
+
+		valid_code = commands[i];
+		cc = sclp_service_call(commands[i], h);
+		if (cc)
+			break;
+		if (h->response_code == SCLP_RC_NORMAL_READ_COMPLETION)
+			return;
+		if (h->response_code != SCLP_RC_INVALID_SCLP_COMMAND)
+			break;
+	}
+	valid_code = 0;
+	report_abort("READ_SCP_INFO failed");
+}
+
+int main(void)
+{
+	report_prefix_push("sclp");
+	find_valid_sclp_code();
+
+	/* Test some basic things */
+	test_instbits();
+	test_priv();
+	test_addressing();
+
+	/* Test the specification exceptions */
+	test_sccb_too_short();
+	test_sccb_unaligned();
+	test_sccb_prefix();
+	test_sccb_high();
+
+	/* Test the expected response codes */
+	test_inval();
+	test_short();
+	test_boundary();
+	test_toolong();
+
+	return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index f1b07cd..07013b2 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -75,3 +75,11 @@ file = stsi.elf
 [smp]
 file = smp.elf
 extra_params =-smp 2
+
+[sclp-1g]
+file = sclp.elf
+extra_params = -m 1G
+
+[sclp-3g]
+file = sclp.elf
+extra_params = -m 3G
-- 
2.24.1

Re: [kvm-unit-tests PATCH v5 4/4] s390x: SCLP unit test

[Thomas Huth]

On 08/01/2020 17.13, Claudio Imbrenda wrote:
> SCLP unit test. Testing the following:
> 
> * Correctly ignoring instruction bits that should be ignored
> * Privileged instruction check
> * Check for addressing exceptions
> * Specification exceptions:
>   - SCCB size less than 8
>   - SCCB unaligned
>   - SCCB overlaps prefix or lowcore
>   - SCCB address higher than 2GB
> * Return codes for
>   - Invalid command
>   - SCCB too short (but at least 8)
>   - SCCB page boundary violation
> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>  s390x/Makefile      |   1 +
>  s390x/sclp.c        | 462 ++++++++++++++++++++++++++++++++++++++++++++
>  s390x/unittests.cfg |   8 +
>  3 files changed, 471 insertions(+)
>  create mode 100644 s390x/sclp.c
[...]
> +/**
> + * Test SCCBs whose address is in the lowcore or prefix area.
> + */
> +static void test_sccb_prefix(void)
> +{
> +	uint8_t scratch[2 * PAGE_SIZE];
> +	uint32_t prefix, new_prefix;
> +	int offset;
> +
> +	/*
> +	 * copy the current lowcore to the future new location, otherwise we
> +	 * will not have a valid lowcore after setting the new prefix.
> +	 */
> +	memcpy(prefix_buf, 0, 2 * PAGE_SIZE);
> +	/* save the current prefix (it's probably going to be 0) */
> +	prefix = stpx();
> +	/*
> +	 * save the current content of absolute pages 0 and 1, so we can
> +	 * restore them after we trash them later on
> +	 */
> +	memcpy(scratch, (void *)(intptr_t)prefix, 2 * PAGE_SIZE);
> +	/* set the new prefix to prefix_buf */
> +	new_prefix = (uint32_t)(intptr_t)prefix_buf;
> +	spx(new_prefix);
> +
> +	/*
> +	 * testing with SCCB addresses in the lowcore; since we can't
> +	 * actually trash the lowcore (unsurprisingly, things break if we
> +	 * do), this will be a read-only test.
> +	 */
> +	for (offset = 0; offset < 2 * PAGE_SIZE; offset += 8)
> +		if (!test_one_sccb(valid_code, MKPTR(offset), 0, PGM_BIT_SPEC, 0))
> +			break;
> +	report(offset == 2 * PAGE_SIZE, "SCCB low pages");
> +
> +	/*
> +	 * this will trash the contents of the two pages at absolute
> +	 * address 0; we will need to restore them later.
> +	 */

I'm still a bit confused by this comment - will SCLP really trash the
contents here, or will there be a specification exception (since
PGM_BIT_SPEC is given below)? ... maybe you could clarify the comment in
case you respin again (or it could be fixed when picking up the patch)?

> +	for (offset = 0; offset < 2 * PAGE_SIZE; offset += 8)
> +		if (!test_one_simple(valid_code, MKPTR(new_prefix + offset), 8, 8, PGM_BIT_SPEC, 0))
> +			break;
> +	report(offset == 2 * PAGE_SIZE, "SCCB prefix pages");
> +
> +	/* restore the previous contents of absolute pages 0 and 1 */
> +	memcpy(prefix_buf, 0, 2 * PAGE_SIZE);
> +	/* restore the prefix to the original value */
> +	spx(prefix);
> +}

Remaining parts look ok to me now, so with the comment clarified:

Reviewed-by: Thomas Huth <thuth@redhat.com>

Re: [kvm-unit-tests PATCH v5 4/4] s390x: SCLP unit test

[Claudio Imbrenda]

On Thu, 9 Jan 2020 13:42:34 +0100
Thomas Huth <thuth@redhat.com> wrote:

> On 08/01/2020 17.13, Claudio Imbrenda wrote:
> > SCLP unit test. Testing the following:
> > 
> > * Correctly ignoring instruction bits that should be ignored
> > * Privileged instruction check
> > * Check for addressing exceptions
> > * Specification exceptions:
> >   - SCCB size less than 8
> >   - SCCB unaligned
> >   - SCCB overlaps prefix or lowcore
> >   - SCCB address higher than 2GB
> > * Return codes for
> >   - Invalid command
> >   - SCCB too short (but at least 8)
> >   - SCCB page boundary violation
> > 
> > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> > ---
> >  s390x/Makefile      |   1 +
> >  s390x/sclp.c        | 462
> > ++++++++++++++++++++++++++++++++++++++++++++ s390x/unittests.cfg |
> >  8 + 3 files changed, 471 insertions(+)
> >  create mode 100644 s390x/sclp.c  
> [...]
> > +/**
> > + * Test SCCBs whose address is in the lowcore or prefix area.
> > + */
> > +static void test_sccb_prefix(void)
> > +{
> > +	uint8_t scratch[2 * PAGE_SIZE];
> > +	uint32_t prefix, new_prefix;
> > +	int offset;
> > +
> > +	/*
> > +	 * copy the current lowcore to the future new location,
> > otherwise we
> > +	 * will not have a valid lowcore after setting the new
> > prefix.
> > +	 */
> > +	memcpy(prefix_buf, 0, 2 * PAGE_SIZE);
> > +	/* save the current prefix (it's probably going to be 0) */
> > +	prefix = stpx();
> > +	/*
> > +	 * save the current content of absolute pages 0 and 1, so
> > we can
> > +	 * restore them after we trash them later on
> > +	 */
> > +	memcpy(scratch, (void *)(intptr_t)prefix, 2 * PAGE_SIZE);
> > +	/* set the new prefix to prefix_buf */
> > +	new_prefix = (uint32_t)(intptr_t)prefix_buf;
> > +	spx(new_prefix);
> > +
> > +	/*
> > +	 * testing with SCCB addresses in the lowcore; since we
> > can't
> > +	 * actually trash the lowcore (unsurprisingly, things
> > break if we
> > +	 * do), this will be a read-only test.
> > +	 */
> > +	for (offset = 0; offset < 2 * PAGE_SIZE; offset += 8)
> > +		if (!test_one_sccb(valid_code, MKPTR(offset), 0,
> > PGM_BIT_SPEC, 0))
> > +			break;
> > +	report(offset == 2 * PAGE_SIZE, "SCCB low pages");
> > +
> > +	/*
> > +	 * this will trash the contents of the two pages at
> > absolute
> > +	 * address 0; we will need to restore them later.
> > +	 */  
> 
> I'm still a bit confused by this comment - will SCLP really trash the
> contents here, or will there be a specification exception (since
> PGM_BIT_SPEC is given below)? ... maybe you could clarify the comment

the SCLP will not touch the pages, because we will receive a
specification exception, as you noticed.

on the other hand... WE will trash the area, because WE will write the
SCCB at those addresses before calling the SCLP. test_one_simple() will
create an SCCB and write it at the address indicated (in our case,
starting at PREFIX, thus ending up starting from absolute address 0)

If you look closely, I used a different function for the lowcore,
because we can't trash that without crashing everything. this means
that the first half of test_sccb_prefix is not as thorough as it could
be (we could be more clever and trash only those parts that are not
vital for the system, but that's probably overkill for now)

I will add some more comments to explain what is happening, and a new
test_one_ro() wrapper to make it more obvious when we are doing a
"read-only" test

> in case you respin again (or it could be fixed when picking up the
> patch)?

I'll need to respin anyway because I noticed a small but important
mistake in the test_addressing function

> > +	for (offset = 0; offset < 2 * PAGE_SIZE; offset += 8)
> > +		if (!test_one_simple(valid_code, MKPTR(new_prefix
> > + offset), 8, 8, PGM_BIT_SPEC, 0))
> > +			break;
> > +	report(offset == 2 * PAGE_SIZE, "SCCB prefix pages");
> > +
> > +	/* restore the previous contents of absolute pages 0 and 1
> > */
> > +	memcpy(prefix_buf, 0, 2 * PAGE_SIZE);
> > +	/* restore the prefix to the original value */
> > +	spx(prefix);
> > +}  
> 
> Remaining parts look ok to me now, so with the comment clarified:
> 
> Reviewed-by: Thomas Huth <thuth@redhat.com>
>