File 0121-pc-bios-s390x-Save-iplb-location-in.patch of Package qemu-linux-user

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File 0121-pc-bios-s390x-Save-iplb-location-in.patch of Package qemu-linux-user

From: Janosch Frank <frankja@linux.ibm.com>
Date: Wed, 4 Mar 2020 06:42:31 -0500
Subject: pc-bios: s390x: Save iplb location in lowcore

Git-commit: 9bfc04f9ef6802fff0fc77130ff345a541783363
References: bsc#1158880

The POP states that for a list directed IPL the IPLB is stored into
memory by the machine loader and its address is stored at offset 0x14
of the lowcore.

ZIPL currently uses the address in offset 0x14 to access the IPLB and
acquire flags about secure boot. If the IPLB address points into
memory which has an unsupported mix of flags set, ZIPL will panic
instead of booting the OS.

As the lowcore can have quite a high entropy for a guest that did drop
out of protected mode (i.e. rebooted) we encountered the ZIPL panic
quite often.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Message-Id: <20200304114231.23493-19-frankja@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Liang Yan <lyan@suse.com>
---
 pc-bios/s390-ccw/jump2ipl.c  |  1 +
 pc-bios/s390-ccw/main.c      |  8 +++++++-
 pc-bios/s390-ccw/netmain.c   |  1 +
 pc-bios/s390-ccw/s390-arch.h | 10 ++++++++--
 pc-bios/s390-ccw/s390-ccw.h  |  1 +
 5 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c
index 266f1502b9675d2a58cb7ae8adbb..1489e5043c85863df9e91951fbd1 100644
--- a/pc-bios/s390-ccw/jump2ipl.c
+++ b/pc-bios/s390-ccw/jump2ipl.c
@@ -35,6 +35,7 @@ void jump_to_IPL_code(uint64_t address)
 {
     /* store the subsystem information _after_ the bootmap was loaded */
     write_subsystem_identification();
+    write_iplb_location();
 
     /* prevent unknown IPL types in the guest */
     if (iplb.pbt == S390_IPL_TYPE_QEMU_SCSI) {
diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
index a69c73349e8f112d6f6ec1a18b8a..3b0823fcb69daf2fcf1d4662cd6b 100644
--- a/pc-bios/s390-ccw/main.c
+++ b/pc-bios/s390-ccw/main.c
@@ -9,6 +9,7 @@
  */
 
 #include "libc.h"
+#include "helper.h"
 #include "s390-arch.h"
 #include "s390-ccw.h"
 #include "cio.h"
@@ -22,7 +23,7 @@ QemuIplParameters qipl;
 IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
 static bool have_iplb;
 static uint16_t cutype;
-LowCore const *lowcore; /* Yes, this *is* a pointer to address 0 */
+LowCore *lowcore; /* Yes, this *is* a pointer to address 0 */
 
 #define LOADPARM_PROMPT "PROMPT  "
 #define LOADPARM_EMPTY  "        "
@@ -42,6 +43,11 @@ void write_subsystem_identification(void)
     *zeroes = 0;
 }
 
+void write_iplb_location(void)
+{
+    lowcore->ptr_iplb = ptr2u32(&iplb);
+}
+
 void panic(const char *string)
 {
     sclp_print(string);
diff --git a/pc-bios/s390-ccw/netmain.c b/pc-bios/s390-ccw/netmain.c
index f3542cb2cf118d96248a728a48a8..81732043d9417205c724a0cee938 100644
--- a/pc-bios/s390-ccw/netmain.c
+++ b/pc-bios/s390-ccw/netmain.c
@@ -40,6 +40,7 @@
 #define DEFAULT_TFTP_RETRIES 20
 
 extern char _start[];
+void write_iplb_location(void) {}
 
 #define KERNEL_ADDR             ((void *)0L)
 #define KERNEL_MAX_SIZE         ((long)_start)
diff --git a/pc-bios/s390-ccw/s390-arch.h b/pc-bios/s390-ccw/s390-arch.h
index 504fc7c2f09878cb6b37e307bb20..5f36361c0223d43439a249e84040 100644
--- a/pc-bios/s390-ccw/s390-arch.h
+++ b/pc-bios/s390-ccw/s390-arch.h
@@ -36,7 +36,13 @@ typedef struct LowCore {
     /* prefix area: defined by architecture */
     PSWLegacy       ipl_psw;                  /* 0x000 */
     uint32_t        ccw1[2];                  /* 0x008 */
-    uint32_t        ccw2[2];                  /* 0x010 */
+    union {
+        uint32_t        ccw2[2];                  /* 0x010 */
+        struct {
+            uint32_t reserved10;
+            uint32_t ptr_iplb;
+        };
+    };
     uint8_t         pad1[0x80 - 0x18];        /* 0x018 */
     uint32_t        ext_params;               /* 0x080 */
     uint16_t        cpu_addr;                 /* 0x084 */
@@ -85,7 +91,7 @@ typedef struct LowCore {
     PSW             io_new_psw;               /* 0x1f0 */
 } __attribute__((packed, aligned(8192))) LowCore;
 
-extern LowCore const *lowcore;
+extern LowCore *lowcore;
 
 static inline void set_prefix(uint32_t address)
 {
diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
index 11bce7d73c85581e561d5802059b..21f27e79906ea297c4480eeaee2e 100644
--- a/pc-bios/s390-ccw/s390-ccw.h
+++ b/pc-bios/s390-ccw/s390-ccw.h
@@ -57,6 +57,7 @@ void consume_io_int(void);
 /* main.c */
 void panic(const char *string);
 void write_subsystem_identification(void);
+void write_iplb_location(void);
 extern char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
 unsigned int get_loadparm_index(void);

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