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Blame SOURCES/kvm-misc-Replace-zero-length-arrays-with-flexible-array-.patch

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From 67878e1306f9ea6ccd30437327147c46de196a36 Mon Sep 17 00:00:00 2001
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From: Thomas Huth <thuth@redhat.com>
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Date: Wed, 11 Nov 2020 12:03:13 -0500
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Subject: [PATCH 13/18] misc: Replace zero-length arrays with flexible array
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 member (manual)
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Thomas Huth <thuth@redhat.com>
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Message-id: <20201111120316.707489-10-thuth@redhat.com>
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Patchwork-id: 99506
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O-Subject: [RHEL-8.4.0 qemu-kvm PATCH v2 09/12] misc: Replace zero-length arrays with flexible array member (manual)
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Bugzilla: 1798506
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RH-Acked-by: Jens Freimann <jfreimann@redhat.com>
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RH-Acked-by: Cornelia Huck <cohuck@redhat.com>
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RH-Acked-by: David Hildenbrand <david@redhat.com>
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From: Philippe Mathieu-Daudé <philmd@redhat.com>
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Description copied from Linux kernel commit from Gustavo A. R. Silva
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(see [3]):
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--v-- description start --v--
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  The current codebase makes use of the zero-length array language
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  extension to the C90 standard, but the preferred mechanism to
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  declare variable-length types such as these ones is a flexible
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  array member [1], introduced in C99:
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  struct foo {
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      int stuff;
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      struct boo array[];
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  };
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  By making use of the mechanism above, we will get a compiler
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  warning in case the flexible array does not occur last in the
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  structure, which will help us prevent some kind of undefined
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  behavior bugs from being unadvertenly introduced [2] to the
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  Linux codebase from now on.
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--^-- description end --^--
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Do the similar housekeeping in the QEMU codebase (which uses
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C99 since commit 7be41675f7cb).
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All these instances of code were found with the help of the
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following command (then manual analysis, without modifying
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structures only having a single flexible array member, such
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QEDTable in block/qed.h):
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  git grep -F '[0];'
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[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
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[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=76497732932f
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[3] https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=17642a2fbd2c1
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Inspired-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
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Reviewed-by: David Hildenbrand <david@redhat.com>
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Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit 880a7817c1a82a93d3f83dfb25dce1f0db629c66)
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Signed-off-by: Thomas Huth <thuth@redhat.com>
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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 block/vmdk.c                      | 2 +-
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 docs/interop/vhost-user.rst       | 4 ++--
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 hw/char/sclpconsole-lm.c          | 2 +-
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 hw/char/sclpconsole.c             | 2 +-
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 hw/s390x/virtio-ccw.c             | 2 +-
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 include/hw/acpi/acpi-defs.h       | 4 ++--
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 include/hw/boards.h               | 2 +-
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 include/hw/s390x/event-facility.h | 2 +-
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 include/hw/s390x/sclp.h           | 8 ++++----
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 target/s390x/ioinst.c             | 2 +-
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 10 files changed, 15 insertions(+), 15 deletions(-)
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diff --git a/block/vmdk.c b/block/vmdk.c
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index 1bd39917290..8ec18f35a53 100644
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--- a/block/vmdk.c
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+++ b/block/vmdk.c
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@@ -187,7 +187,7 @@ typedef struct VmdkMetaData {
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 typedef struct VmdkGrainMarker {
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     uint64_t lba;
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     uint32_t size;
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-    uint8_t  data[0];
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+    uint8_t  data[];
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 } QEMU_PACKED VmdkGrainMarker;
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 enum {
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diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
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index 7827b710aa0..71b20ce83dd 100644
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--- a/docs/interop/vhost-user.rst
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+++ b/docs/interop/vhost-user.rst
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@@ -563,7 +563,7 @@ For split virtqueue, queue region can be implemented as:
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       uint16_t used_idx;
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       /* Used to track the state of each descriptor in descriptor table */
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-      DescStateSplit desc[0];
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+      DescStateSplit desc[];
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   } QueueRegionSplit;
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 To track inflight I/O, the queue region should be processed as follows:
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@@ -685,7 +685,7 @@ For packed virtqueue, queue region can be implemented as:
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       uint8_t padding[7];
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       /* Used to track the state of each descriptor fetched from descriptor ring */
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-      DescStatePacked desc[0];
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+      DescStatePacked desc[];
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   } QueueRegionPacked;
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 To track inflight I/O, the queue region should be processed as follows:
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diff --git a/hw/char/sclpconsole-lm.c b/hw/char/sclpconsole-lm.c
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index 392606259d5..a9a6f2b204c 100644
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--- a/hw/char/sclpconsole-lm.c
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+++ b/hw/char/sclpconsole-lm.c
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@@ -31,7 +31,7 @@
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 typedef struct OprtnsCommand {
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     EventBufferHeader header;
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     MDMSU message_unit;
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-    char data[0];
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+    char data[];
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 } QEMU_PACKED OprtnsCommand;
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 /* max size for line-mode data in 4K SCCB page */
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diff --git a/hw/char/sclpconsole.c b/hw/char/sclpconsole.c
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index da126f0133f..55697130a0a 100644
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--- a/hw/char/sclpconsole.c
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+++ b/hw/char/sclpconsole.c
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@@ -25,7 +25,7 @@
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 typedef struct ASCIIConsoleData {
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     EventBufferHeader ebh;
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-    char data[0];
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+    char data[];
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 } QEMU_PACKED ASCIIConsoleData;
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 /* max size for ASCII data in 4K SCCB page */
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diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
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index 6580ce5907d..aa2c75a49c6 100644
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--- a/hw/s390x/virtio-ccw.c
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+++ b/hw/s390x/virtio-ccw.c
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@@ -193,7 +193,7 @@ typedef struct VirtioThinintInfo {
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 typedef struct VirtioRevInfo {
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     uint16_t revision;
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     uint16_t length;
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-    uint8_t data[0];
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+    uint8_t data[];
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 } QEMU_PACKED VirtioRevInfo;
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 /* Specify where the virtqueues for the subchannel are in guest memory. */
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diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
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index 57a3f58b0c9..b80188b430f 100644
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--- a/include/hw/acpi/acpi-defs.h
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+++ b/include/hw/acpi/acpi-defs.h
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@@ -152,7 +152,7 @@ typedef struct AcpiSerialPortConsoleRedirection
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  */
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 struct AcpiRsdtDescriptorRev1 {
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     ACPI_TABLE_HEADER_DEF       /* ACPI common table header */
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-    uint32_t table_offset_entry[0];  /* Array of pointers to other */
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+    uint32_t table_offset_entry[];  /* Array of pointers to other */
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     /* ACPI tables */
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 } QEMU_PACKED;
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 typedef struct AcpiRsdtDescriptorRev1 AcpiRsdtDescriptorRev1;
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@@ -162,7 +162,7 @@ typedef struct AcpiRsdtDescriptorRev1 AcpiRsdtDescriptorRev1;
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  */
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 struct AcpiXsdtDescriptorRev2 {
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     ACPI_TABLE_HEADER_DEF       /* ACPI common table header */
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-    uint64_t table_offset_entry[0];  /* Array of pointers to other */
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+    uint64_t table_offset_entry[];  /* Array of pointers to other */
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     /* ACPI tables */
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 } QEMU_PACKED;
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 typedef struct AcpiXsdtDescriptorRev2 AcpiXsdtDescriptorRev2;
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diff --git a/include/hw/boards.h b/include/hw/boards.h
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index 2920bdef5b4..a5e92f6c373 100644
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--- a/include/hw/boards.h
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+++ b/include/hw/boards.h
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@@ -101,7 +101,7 @@ typedef struct CPUArchId {
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  */
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 typedef struct {
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     int len;
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-    CPUArchId cpus[0];
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+    CPUArchId cpus[];
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 } CPUArchIdList;
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 /**
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diff --git a/include/hw/s390x/event-facility.h b/include/hw/s390x/event-facility.h
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index bdc32a3c091..700a610f33c 100644
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--- a/include/hw/s390x/event-facility.h
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+++ b/include/hw/s390x/event-facility.h
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@@ -122,7 +122,7 @@ typedef struct MDBO {
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 typedef struct MDB {
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     MdbHeader header;
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-    MDBO mdbo[0];
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+    MDBO mdbo[];
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 } QEMU_PACKED MDB;
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 typedef struct SclpMsg {
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diff --git a/include/hw/s390x/sclp.h b/include/hw/s390x/sclp.h
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index df2fa4169b0..62e2aa1d9f1 100644
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--- a/include/hw/s390x/sclp.h
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+++ b/include/hw/s390x/sclp.h
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@@ -133,7 +133,7 @@ typedef struct ReadInfo {
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     uint16_t highest_cpu;
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     uint8_t  _reserved5[124 - 122];     /* 122-123 */
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     uint32_t hmfai;
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-    struct CPUEntry entries[0];
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+    struct CPUEntry entries[];
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 } QEMU_PACKED ReadInfo;
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 typedef struct ReadCpuInfo {
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@@ -143,7 +143,7 @@ typedef struct ReadCpuInfo {
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     uint16_t nr_standby;            /* 12-13 */
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     uint16_t offset_standby;        /* 14-15 */
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     uint8_t reserved0[24-16];       /* 16-23 */
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-    struct CPUEntry entries[0];
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+    struct CPUEntry entries[];
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 } QEMU_PACKED ReadCpuInfo;
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 typedef struct ReadStorageElementInfo {
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@@ -152,7 +152,7 @@ typedef struct ReadStorageElementInfo {
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     uint16_t assigned;
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     uint16_t standby;
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     uint8_t _reserved0[16 - 14]; /* 14-15 */
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-    uint32_t entries[0];
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+    uint32_t entries[];
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 } QEMU_PACKED ReadStorageElementInfo;
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 typedef struct AttachStorageElement {
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@@ -160,7 +160,7 @@ typedef struct AttachStorageElement {
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     uint8_t _reserved0[10 - 8];  /* 8-9 */
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     uint16_t assigned;
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     uint8_t _reserved1[16 - 12]; /* 12-15 */
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-    uint32_t entries[0];
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+    uint32_t entries[];
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 } QEMU_PACKED AttachStorageElement;
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 typedef struct AssignStorage {
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diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
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index b6be300cc48..a412926d278 100644
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--- a/target/s390x/ioinst.c
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+++ b/target/s390x/ioinst.c
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@@ -387,7 +387,7 @@ typedef struct ChscResp {
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     uint16_t len;
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     uint16_t code;
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     uint32_t param;
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-    char data[0];
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+    char data[];
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 } QEMU_PACKED ChscResp;
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 #define CHSC_MIN_RESP_LEN 0x0008
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-- 
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2.27.0
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