[3/3] uuid: Make qemu_uuid_bswap() take and return a QemuUUID

Message ID 20181210112649.11581-4-peter.maydell@linaro.org
State Accepted
Headers show
Series
  • block: fix last address-of-packed-member warnings
Related show

Commit Message

Peter Maydell Dec. 10, 2018, 11:26 a.m.
Currently qemu_uuid_bswap() takes a pointer to the QemuUUID to
be byte-swapped. This means it can't be used when the UUID
to be swapped is in a packed member of a struct. It's also
out of line with the general bswap*() functions we provide
in bswap.h, which take the value to be swapped and return it.

Make qemu_uuid_bswap() take a QemuUUID and return the swapped version.

This fixes some clang warnings about taking the address of
a packed struct member in block/vdi.c.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

---
 include/qemu/uuid.h  |  2 +-
 block/vdi.c          | 16 ++++++++--------
 hw/acpi/vmgenid.c    |  6 ++----
 tests/vmgenid-test.c |  2 +-
 util/uuid.c          | 10 +++++-----
 5 files changed, 17 insertions(+), 19 deletions(-)

-- 
2.19.2

Comments

Marc-André Lureau Dec. 10, 2018, 11:37 a.m. | #1
On Mon, Dec 10, 2018 at 3:27 PM Peter Maydell <peter.maydell@linaro.org> wrote:
>

> Currently qemu_uuid_bswap() takes a pointer to the QemuUUID to

> be byte-swapped. This means it can't be used when the UUID

> to be swapped is in a packed member of a struct. It's also

> out of line with the general bswap*() functions we provide

> in bswap.h, which take the value to be swapped and return it.

>

> Make qemu_uuid_bswap() take a QemuUUID and return the swapped version.

>

> This fixes some clang warnings about taking the address of

> a packed struct member in block/vdi.c.

>

> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>


Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>


> ---

>  include/qemu/uuid.h  |  2 +-

>  block/vdi.c          | 16 ++++++++--------

>  hw/acpi/vmgenid.c    |  6 ++----

>  tests/vmgenid-test.c |  2 +-

>  util/uuid.c          | 10 +++++-----

>  5 files changed, 17 insertions(+), 19 deletions(-)

>

> diff --git a/include/qemu/uuid.h b/include/qemu/uuid.h

> index 09489ce5c5e..037357d990b 100644

> --- a/include/qemu/uuid.h

> +++ b/include/qemu/uuid.h

> @@ -56,6 +56,6 @@ char *qemu_uuid_unparse_strdup(const QemuUUID *uuid);

>

>  int qemu_uuid_parse(const char *str, QemuUUID *uuid);

>

> -void qemu_uuid_bswap(QemuUUID *uuid);

> +QemuUUID qemu_uuid_bswap(QemuUUID uuid);

>

>  #endif

> diff --git a/block/vdi.c b/block/vdi.c

> index 4cc726047c3..0c34f6bae46 100644

> --- a/block/vdi.c

> +++ b/block/vdi.c

> @@ -203,10 +203,10 @@ static void vdi_header_to_cpu(VdiHeader *header)

>      header->block_extra = le32_to_cpu(header->block_extra);

>      header->blocks_in_image = le32_to_cpu(header->blocks_in_image);

>      header->blocks_allocated = le32_to_cpu(header->blocks_allocated);

> -    qemu_uuid_bswap(&header->uuid_image);

> -    qemu_uuid_bswap(&header->uuid_last_snap);

> -    qemu_uuid_bswap(&header->uuid_link);

> -    qemu_uuid_bswap(&header->uuid_parent);

> +    header->uuid_image = qemu_uuid_bswap(header->uuid_image);

> +    header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap);

> +    header->uuid_link = qemu_uuid_bswap(header->uuid_link);

> +    header->uuid_parent = qemu_uuid_bswap(header->uuid_parent);

>  }

>

>  static void vdi_header_to_le(VdiHeader *header)

> @@ -227,10 +227,10 @@ static void vdi_header_to_le(VdiHeader *header)

>      header->block_extra = cpu_to_le32(header->block_extra);

>      header->blocks_in_image = cpu_to_le32(header->blocks_in_image);

>      header->blocks_allocated = cpu_to_le32(header->blocks_allocated);

> -    qemu_uuid_bswap(&header->uuid_image);

> -    qemu_uuid_bswap(&header->uuid_last_snap);

> -    qemu_uuid_bswap(&header->uuid_link);

> -    qemu_uuid_bswap(&header->uuid_parent);

> +    header->uuid_image = qemu_uuid_bswap(header->uuid_image);

> +    header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap);

> +    header->uuid_link = qemu_uuid_bswap(header->uuid_link);

> +    header->uuid_parent = qemu_uuid_bswap(header->uuid_parent);

>  }

>

>  static void vdi_header_print(VdiHeader *header)

> diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c

> index d78b579a201..02717a8b0dc 100644

> --- a/hw/acpi/vmgenid.c

> +++ b/hw/acpi/vmgenid.c

> @@ -30,8 +30,7 @@ void vmgenid_build_acpi(VmGenIdState *vms, GArray *table_data, GArray *guid,

>       * first, since that's what the guest expects

>       */

>      g_array_set_size(guid, VMGENID_FW_CFG_SIZE - ARRAY_SIZE(guid_le.data));

> -    guid_le = vms->guid;

> -    qemu_uuid_bswap(&guid_le);

> +    guid_le = qemu_uuid_bswap(vms->guid);

>      /* The GUID is written at a fixed offset into the fw_cfg file

>       * in order to implement the "OVMF SDT Header probe suppressor"

>       * see docs/specs/vmgenid.txt for more details

> @@ -149,8 +148,7 @@ static void vmgenid_update_guest(VmGenIdState *vms)

>               * however, will expect the fields to be little-endian.

>               * Perform a byte swap immediately before writing.

>               */

> -            guid_le = vms->guid;

> -            qemu_uuid_bswap(&guid_le);

> +            guid_le = qemu_uuid_bswap(vms->guid);

>              /* The GUID is written at a fixed offset into the fw_cfg file

>               * in order to implement the "OVMF SDT Header probe suppressor"

>               * see docs/specs/vmgenid.txt for more details.

> diff --git a/tests/vmgenid-test.c b/tests/vmgenid-test.c

> index 0a6fb55f2eb..98db43f5a65 100644

> --- a/tests/vmgenid-test.c

> +++ b/tests/vmgenid-test.c

> @@ -110,7 +110,7 @@ static void read_guid_from_memory(QemuUUID *guid)

>      /* The GUID is in little-endian format in the guest, while QEMU

>       * uses big-endian.  Swap after reading.

>       */

> -    qemu_uuid_bswap(guid);

> +    *guid = qemu_uuid_bswap(*guid);

>  }

>

>  static void read_guid_from_monitor(QemuUUID *guid)

> diff --git a/util/uuid.c b/util/uuid.c

> index ebf06c049ad..5787f0978c1 100644

> --- a/util/uuid.c

> +++ b/util/uuid.c

> @@ -110,10 +110,10 @@ int qemu_uuid_parse(const char *str, QemuUUID *uuid)

>

>  /* Swap from UUID format endian (BE) to the opposite or vice versa.

>   */

> -void qemu_uuid_bswap(QemuUUID *uuid)

> +QemuUUID qemu_uuid_bswap(QemuUUID uuid)

>  {

> -    assert(QEMU_PTR_IS_ALIGNED(uuid, sizeof(uint32_t)));

> -    bswap32s(&uuid->fields.time_low);

> -    bswap16s(&uuid->fields.time_mid);

> -    bswap16s(&uuid->fields.time_high_and_version);

> +    bswap32s(&uuid.fields.time_low);

> +    bswap16s(&uuid.fields.time_mid);

> +    bswap16s(&uuid.fields.time_high_and_version);

> +    return uuid;

>  }

> --

> 2.19.2

>

>



-- 
Marc-André Lureau
Michael S. Tsirkin Dec. 10, 2018, 5:57 p.m. | #2
On Mon, Dec 10, 2018 at 11:26:49AM +0000, Peter Maydell wrote:
> Currently qemu_uuid_bswap() takes a pointer to the QemuUUID to

> be byte-swapped. This means it can't be used when the UUID

> to be swapped is in a packed member of a struct. It's also

> out of line with the general bswap*() functions we provide

> in bswap.h, which take the value to be swapped and return it.

> 

> Make qemu_uuid_bswap() take a QemuUUID and return the swapped version.

> 

> This fixes some clang warnings about taking the address of

> a packed struct member in block/vdi.c.

> 

> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>


For acpi:

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>


> ---

>  include/qemu/uuid.h  |  2 +-

>  block/vdi.c          | 16 ++++++++--------

>  hw/acpi/vmgenid.c    |  6 ++----

>  tests/vmgenid-test.c |  2 +-

>  util/uuid.c          | 10 +++++-----

>  5 files changed, 17 insertions(+), 19 deletions(-)

> 

> diff --git a/include/qemu/uuid.h b/include/qemu/uuid.h

> index 09489ce5c5e..037357d990b 100644

> --- a/include/qemu/uuid.h

> +++ b/include/qemu/uuid.h

> @@ -56,6 +56,6 @@ char *qemu_uuid_unparse_strdup(const QemuUUID *uuid);

>  

>  int qemu_uuid_parse(const char *str, QemuUUID *uuid);

>  

> -void qemu_uuid_bswap(QemuUUID *uuid);

> +QemuUUID qemu_uuid_bswap(QemuUUID uuid);

>  

>  #endif

> diff --git a/block/vdi.c b/block/vdi.c

> index 4cc726047c3..0c34f6bae46 100644

> --- a/block/vdi.c

> +++ b/block/vdi.c

> @@ -203,10 +203,10 @@ static void vdi_header_to_cpu(VdiHeader *header)

>      header->block_extra = le32_to_cpu(header->block_extra);

>      header->blocks_in_image = le32_to_cpu(header->blocks_in_image);

>      header->blocks_allocated = le32_to_cpu(header->blocks_allocated);

> -    qemu_uuid_bswap(&header->uuid_image);

> -    qemu_uuid_bswap(&header->uuid_last_snap);

> -    qemu_uuid_bswap(&header->uuid_link);

> -    qemu_uuid_bswap(&header->uuid_parent);

> +    header->uuid_image = qemu_uuid_bswap(header->uuid_image);

> +    header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap);

> +    header->uuid_link = qemu_uuid_bswap(header->uuid_link);

> +    header->uuid_parent = qemu_uuid_bswap(header->uuid_parent);

>  }

>  

>  static void vdi_header_to_le(VdiHeader *header)

> @@ -227,10 +227,10 @@ static void vdi_header_to_le(VdiHeader *header)

>      header->block_extra = cpu_to_le32(header->block_extra);

>      header->blocks_in_image = cpu_to_le32(header->blocks_in_image);

>      header->blocks_allocated = cpu_to_le32(header->blocks_allocated);

> -    qemu_uuid_bswap(&header->uuid_image);

> -    qemu_uuid_bswap(&header->uuid_last_snap);

> -    qemu_uuid_bswap(&header->uuid_link);

> -    qemu_uuid_bswap(&header->uuid_parent);

> +    header->uuid_image = qemu_uuid_bswap(header->uuid_image);

> +    header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap);

> +    header->uuid_link = qemu_uuid_bswap(header->uuid_link);

> +    header->uuid_parent = qemu_uuid_bswap(header->uuid_parent);

>  }

>  

>  static void vdi_header_print(VdiHeader *header)

> diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c

> index d78b579a201..02717a8b0dc 100644

> --- a/hw/acpi/vmgenid.c

> +++ b/hw/acpi/vmgenid.c

> @@ -30,8 +30,7 @@ void vmgenid_build_acpi(VmGenIdState *vms, GArray *table_data, GArray *guid,

>       * first, since that's what the guest expects

>       */

>      g_array_set_size(guid, VMGENID_FW_CFG_SIZE - ARRAY_SIZE(guid_le.data));

> -    guid_le = vms->guid;

> -    qemu_uuid_bswap(&guid_le);

> +    guid_le = qemu_uuid_bswap(vms->guid);

>      /* The GUID is written at a fixed offset into the fw_cfg file

>       * in order to implement the "OVMF SDT Header probe suppressor"

>       * see docs/specs/vmgenid.txt for more details

> @@ -149,8 +148,7 @@ static void vmgenid_update_guest(VmGenIdState *vms)

>               * however, will expect the fields to be little-endian.

>               * Perform a byte swap immediately before writing.

>               */

> -            guid_le = vms->guid;

> -            qemu_uuid_bswap(&guid_le);

> +            guid_le = qemu_uuid_bswap(vms->guid);

>              /* The GUID is written at a fixed offset into the fw_cfg file

>               * in order to implement the "OVMF SDT Header probe suppressor"

>               * see docs/specs/vmgenid.txt for more details.

> diff --git a/tests/vmgenid-test.c b/tests/vmgenid-test.c

> index 0a6fb55f2eb..98db43f5a65 100644

> --- a/tests/vmgenid-test.c

> +++ b/tests/vmgenid-test.c

> @@ -110,7 +110,7 @@ static void read_guid_from_memory(QemuUUID *guid)

>      /* The GUID is in little-endian format in the guest, while QEMU

>       * uses big-endian.  Swap after reading.

>       */

> -    qemu_uuid_bswap(guid);

> +    *guid = qemu_uuid_bswap(*guid);

>  }

>  

>  static void read_guid_from_monitor(QemuUUID *guid)

> diff --git a/util/uuid.c b/util/uuid.c

> index ebf06c049ad..5787f0978c1 100644

> --- a/util/uuid.c

> +++ b/util/uuid.c

> @@ -110,10 +110,10 @@ int qemu_uuid_parse(const char *str, QemuUUID *uuid)

>  

>  /* Swap from UUID format endian (BE) to the opposite or vice versa.

>   */

> -void qemu_uuid_bswap(QemuUUID *uuid)

> +QemuUUID qemu_uuid_bswap(QemuUUID uuid)

>  {

> -    assert(QEMU_PTR_IS_ALIGNED(uuid, sizeof(uint32_t)));

> -    bswap32s(&uuid->fields.time_low);

> -    bswap16s(&uuid->fields.time_mid);

> -    bswap16s(&uuid->fields.time_high_and_version);

> +    bswap32s(&uuid.fields.time_low);

> +    bswap16s(&uuid.fields.time_mid);

> +    bswap16s(&uuid.fields.time_high_and_version);

> +    return uuid;

>  }

> -- 

> 2.19.2

Patch

diff --git a/include/qemu/uuid.h b/include/qemu/uuid.h
index 09489ce5c5e..037357d990b 100644
--- a/include/qemu/uuid.h
+++ b/include/qemu/uuid.h
@@ -56,6 +56,6 @@  char *qemu_uuid_unparse_strdup(const QemuUUID *uuid);
 
 int qemu_uuid_parse(const char *str, QemuUUID *uuid);
 
-void qemu_uuid_bswap(QemuUUID *uuid);
+QemuUUID qemu_uuid_bswap(QemuUUID uuid);
 
 #endif
diff --git a/block/vdi.c b/block/vdi.c
index 4cc726047c3..0c34f6bae46 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -203,10 +203,10 @@  static void vdi_header_to_cpu(VdiHeader *header)
     header->block_extra = le32_to_cpu(header->block_extra);
     header->blocks_in_image = le32_to_cpu(header->blocks_in_image);
     header->blocks_allocated = le32_to_cpu(header->blocks_allocated);
-    qemu_uuid_bswap(&header->uuid_image);
-    qemu_uuid_bswap(&header->uuid_last_snap);
-    qemu_uuid_bswap(&header->uuid_link);
-    qemu_uuid_bswap(&header->uuid_parent);
+    header->uuid_image = qemu_uuid_bswap(header->uuid_image);
+    header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap);
+    header->uuid_link = qemu_uuid_bswap(header->uuid_link);
+    header->uuid_parent = qemu_uuid_bswap(header->uuid_parent);
 }
 
 static void vdi_header_to_le(VdiHeader *header)
@@ -227,10 +227,10 @@  static void vdi_header_to_le(VdiHeader *header)
     header->block_extra = cpu_to_le32(header->block_extra);
     header->blocks_in_image = cpu_to_le32(header->blocks_in_image);
     header->blocks_allocated = cpu_to_le32(header->blocks_allocated);
-    qemu_uuid_bswap(&header->uuid_image);
-    qemu_uuid_bswap(&header->uuid_last_snap);
-    qemu_uuid_bswap(&header->uuid_link);
-    qemu_uuid_bswap(&header->uuid_parent);
+    header->uuid_image = qemu_uuid_bswap(header->uuid_image);
+    header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap);
+    header->uuid_link = qemu_uuid_bswap(header->uuid_link);
+    header->uuid_parent = qemu_uuid_bswap(header->uuid_parent);
 }
 
 static void vdi_header_print(VdiHeader *header)
diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c
index d78b579a201..02717a8b0dc 100644
--- a/hw/acpi/vmgenid.c
+++ b/hw/acpi/vmgenid.c
@@ -30,8 +30,7 @@  void vmgenid_build_acpi(VmGenIdState *vms, GArray *table_data, GArray *guid,
      * first, since that's what the guest expects
      */
     g_array_set_size(guid, VMGENID_FW_CFG_SIZE - ARRAY_SIZE(guid_le.data));
-    guid_le = vms->guid;
-    qemu_uuid_bswap(&guid_le);
+    guid_le = qemu_uuid_bswap(vms->guid);
     /* The GUID is written at a fixed offset into the fw_cfg file
      * in order to implement the "OVMF SDT Header probe suppressor"
      * see docs/specs/vmgenid.txt for more details
@@ -149,8 +148,7 @@  static void vmgenid_update_guest(VmGenIdState *vms)
              * however, will expect the fields to be little-endian.
              * Perform a byte swap immediately before writing.
              */
-            guid_le = vms->guid;
-            qemu_uuid_bswap(&guid_le);
+            guid_le = qemu_uuid_bswap(vms->guid);
             /* The GUID is written at a fixed offset into the fw_cfg file
              * in order to implement the "OVMF SDT Header probe suppressor"
              * see docs/specs/vmgenid.txt for more details.
diff --git a/tests/vmgenid-test.c b/tests/vmgenid-test.c
index 0a6fb55f2eb..98db43f5a65 100644
--- a/tests/vmgenid-test.c
+++ b/tests/vmgenid-test.c
@@ -110,7 +110,7 @@  static void read_guid_from_memory(QemuUUID *guid)
     /* The GUID is in little-endian format in the guest, while QEMU
      * uses big-endian.  Swap after reading.
      */
-    qemu_uuid_bswap(guid);
+    *guid = qemu_uuid_bswap(*guid);
 }
 
 static void read_guid_from_monitor(QemuUUID *guid)
diff --git a/util/uuid.c b/util/uuid.c
index ebf06c049ad..5787f0978c1 100644
--- a/util/uuid.c
+++ b/util/uuid.c
@@ -110,10 +110,10 @@  int qemu_uuid_parse(const char *str, QemuUUID *uuid)
 
 /* Swap from UUID format endian (BE) to the opposite or vice versa.
  */
-void qemu_uuid_bswap(QemuUUID *uuid)
+QemuUUID qemu_uuid_bswap(QemuUUID uuid)
 {
-    assert(QEMU_PTR_IS_ALIGNED(uuid, sizeof(uint32_t)));
-    bswap32s(&uuid->fields.time_low);
-    bswap16s(&uuid->fields.time_mid);
-    bswap16s(&uuid->fields.time_high_and_version);
+    bswap32s(&uuid.fields.time_low);
+    bswap16s(&uuid.fields.time_mid);
+    bswap16s(&uuid.fields.time_high_and_version);
+    return uuid;
 }