[kvm-unit-tests PATCH v4 2/2] s390x: sclp: Implement SCLP_RC_INSUFFICIENT_SCCB_LENGTH

Pierre Morel
2023-05-30T12:53:35Z

If SCLP_CMDW_READ_SCP_INFO fails due to a short buffer, retry
with a greater buffer.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
lib/s390x/sclp.c | 58 +++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 50 insertions(+), 8 deletions(-)

diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
index 34a31da..9d51ca4 100644
--- a/lib/s390x/sclp.c
+++ b/lib/s390x/sclp.c
@@ -17,13 +17,14 @@
#include "sclp.h"
#include <alloc_phys.h>
#include <alloc_page.h>
+#include <asm/facility.h>

extern unsigned long stacktop;

static uint64_t storage_increment_size;
static uint64_t max_ram_size;
static uint64_t ram_size;
-char _read_info[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
+char _read_info[2 * PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
static ReadInfo *read_info;
struct sclp_facilities sclp_facilities;

@@ -89,10 +90,41 @@ void sclp_clear_busy(void)
spin_unlock(&sclp_lock);
}

-static void sclp_read_scp_info(ReadInfo *ri, int length)
+static bool sclp_read_scp_info_extended(unsigned int command, ReadInfo *ri)
+{
+ int cc;
+
+ if (!test_facility(140)) {
+ report_abort("S390_FEAT_EXTENDED_LENGTH_SCCB missing");
+ return false;
+ }
+ if (ri->h.length > (2 * PAGE_SIZE)) {
+ report_abort("SCLP_READ_INFO expected size too big");
+ return false;
+ }
+
+ sclp_mark_busy();
+ memset(&ri->h, 0, sizeof(ri->h));
+ ri->h.length = 2 * PAGE_SIZE;
+
+ cc = sclp_service_call(command, ri);
+ if (cc) {
+ report_abort("SCLP_READ_INFO error");
+ return false;
+ }
+ if (ri->h.response_code != SCLP_RC_NORMAL_READ_COMPLETION) {
+ report_abort("SCLP_READ_INFO error %02x", ri->h.response_code);
+ return false;
+ }
+
+ return true;
+}
+
+static void sclp_read_scp_info(ReadInfo *ri)
{
unsigned int commands[] = { SCLP_CMDW_READ_SCP_INFO_FORCED,
SCLP_CMDW_READ_SCP_INFO };
+ int length = PAGE_SIZE;
int i, cc;

for (i = 0; i < ARRAY_SIZE(commands); i++) {
@@ -101,19 +133,29 @@ static void sclp_read_scp_info(ReadInfo *ri, int length)
ri->h.length = length;

cc = sclp_service_call(commands[i], ri);
- if (cc)
- break;
- if (ri->h.response_code == SCLP_RC_NORMAL_READ_COMPLETION)
+ if (cc) {
+ report_abort("SCLP_READ_INFO error");
return;
- if (ri->h.response_code != SCLP_RC_INVALID_SCLP_COMMAND)
+ }
+
+ switch (ri->h.response_code) {
+ case SCLP_RC_NORMAL_READ_COMPLETION:
+ return;
+ case SCLP_RC_INVALID_SCLP_COMMAND:
break;
+ case SCLP_RC_INSUFFICIENT_SCCB_LENGTH:
+ sclp_read_scp_info_extended(commands[i], ri);
+ return;
+ default:
+ report_abort("READ_SCP_INFO failed");
+ return;
+ }
}
- report_abort("READ_SCP_INFO failed");
}

void sclp_read_info(void)
{
- sclp_read_scp_info((void *)_read_info, SCCB_SIZE);
+ sclp_read_scp_info((void *)_read_info);
read_info = (ReadInfo *)_read_info;
}

--
2.31.1