On 1/29/26 5:54 PM, Farhan Ali wrote:
On 1/27/2026 8:15 AM, [email protected] wrote:
From: Jared Rossi <[email protected]>
Call Logical Processor (CLP) Architecture is used for managing PCI
functions on
s390x. Define and include the structures and routines needed to
interact with
PCI devices during IPL.
Signed-off-by: Jared Rossi <[email protected]>
---
pc-bios/s390-ccw/Makefile | 2 +-
pc-bios/s390-ccw/clp.c | 96 +++++++++++++++++++++++++++++++++++++++
pc-bios/s390-ccw/clp.h | 24 ++++++++++
3 files changed, 121 insertions(+), 1 deletion(-)
create mode 100644 pc-bios/s390-ccw/clp.c
create mode 100644 pc-bios/s390-ccw/clp.h
diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
index 259cff09db..9c29548f84 100644
--- a/pc-bios/s390-ccw/Makefile
+++ b/pc-bios/s390-ccw/Makefile
@@ -35,7 +35,7 @@ QEMU_DGFLAGS = -MMD -MP -MT $@ -MF $(@D)/$(*F).d
OBJECTS = start.o main.o bootmap.o jump2ipl.o sclp.o menu.o
netmain.o \
virtio.o virtio-net.o virtio-scsi.o virtio-blkdev.o cio.o
dasd-ipl.o \
- virtio-ccw.o
+ virtio-ccw.o clp.o
SLOF_DIR := $(SRC_PATH)/../../roms/SLOF
diff --git a/pc-bios/s390-ccw/clp.c b/pc-bios/s390-ccw/clp.c
new file mode 100644
index 0000000000..2a14bb9b73
--- /dev/null
+++ b/pc-bios/s390-ccw/clp.c
@@ -0,0 +1,96 @@
+/*
+ * Call Logical Processor (CLP) architecture
+ *
+ * Copyright 2025 IBM Corp.
+ * Author(s): Jared Rossi <[email protected]>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "clp.h"
+#include <stdio.h>
+#include <string.h>
+
+int clp_pci(void *data)
+{
+ struct { uint8_t _[2048]; } *req = data;
The architecture specifies that size of the request + response block
size can be maximum of 8192 bytes. If I understand correctly I think
QEMU (similar to kernel) uses CLP_BLK_SIZE when calculating the
CLP_FH_LIST_NR_ENTRIES, so it assumes that the request + response
block is 4096. So we can return more than 2048 bytes here and overflow.
I think we should use at least CLP_BLK_SIZE here instead of 2048 or
set this to the maximum possible value of 8192.
Thanks
Farhan
Thanks for pointing that out, I'll fix it.
Regards,
Jared Rossi
+ int cc = 3;
+
+ asm volatile (
+ " .insn rrf,0xb9a00000,0,%[req],0,2\n"
+ " ipm %[cc]\n"
+ " srl %[cc],28\n"
+ : [cc] "+d" (cc), "+m" (*req)
+ : [req] "a" (req)
+ : "cc");
+ return cc;
+}
+
