[Qemu-devel] [PATCH v2] migration: Don't use *_to_cpup() and cpu_to_*w()

[Qemu-devel] [PATCH v2] migration: Don't use *_to_cpup() and cpu_to_*w()

[Peter Maydell]

The *_to_cpup() and cpu_to_*w() functions just compose a pointer
dereference with a byteswap. Instead use ld*_p() and st*_p(),
which handle potential pointer misalignment and avoid the need
to cast the pointer.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Changes v1->v2: fix cpu_to_*w() uses too.

The motivation here is that I'd like to get rid of _to_cpup()
and cpu_to_*w() entirely: we don't have many places that use them.
---
 migration/migration.c | 12 ++++++------
 migration/savevm.c    |  4 ++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 7ecbade..551da0a 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1381,7 +1381,7 @@ static void *source_return_path_thread(void *opaque)
         /* OK, we have the message and the data */
         switch (header_type) {
         case MIG_RP_MSG_SHUT:
-            sibling_error = be32_to_cpup((uint32_t *)buf);
+            sibling_error = ldl_be_p(buf);
             trace_source_return_path_thread_shut(sibling_error);
             if (sibling_error) {
                 error_report("RP: Sibling indicated error %d", sibling_error);
@@ -1395,13 +1395,13 @@ static void *source_return_path_thread(void *opaque)
             goto out;
 
         case MIG_RP_MSG_PONG:
-            tmp32 = be32_to_cpup((uint32_t *)buf);
+            tmp32 = ldl_be_p(buf);
             trace_source_return_path_thread_pong(tmp32);
             break;
 
         case MIG_RP_MSG_REQ_PAGES:
-            start = be64_to_cpup((uint64_t *)buf);
-            len = be32_to_cpup((uint32_t *)(buf + 8));
+            start = ldq_be_p(buf);
+            len = ldl_be_p(buf + 8);
             migrate_handle_rp_req_pages(ms, NULL, start, len);
             break;
 
@@ -1409,8 +1409,8 @@ static void *source_return_path_thread(void *opaque)
             expected_len = 12 + 1; /* header + termination */
 
             if (header_len >= expected_len) {
-                start = be64_to_cpup((uint64_t *)buf);
-                len = be32_to_cpup((uint32_t *)(buf + 8));
+                start = ldq_be_p(buf);
+                len = ldl_be_p(buf + 8);
                 /* Now we expect an idstr */
                 tmp32 = buf[12]; /* Length of the following idstr */
                 buf[13 + tmp32] = '\0';
diff --git a/migration/savevm.c b/migration/savevm.c
index 6c21231..7da46a6 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -822,9 +822,9 @@ void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name,
     buf[tmplen++] = '\0';
 
     for (t = 0; t < len; t++) {
-        cpu_to_be64w((uint64_t *)(buf + tmplen), start_list[t]);
+        stq_be_p(buf + tmplen, start_list[t]);
         tmplen += 8;
-        cpu_to_be64w((uint64_t *)(buf + tmplen), length_list[t]);
+        stq_be_p(buf + tmplen, length_list[t]);
         tmplen += 8;
     }
     qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RAM_DISCARD, tmplen, buf);
-- 
1.9.1

Re: [Qemu-devel] [PATCH v2] migration: Don't use *_to_cpup() and cpu_to_*w()

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 825 bytes --]

On 06/10/2016 10:09 AM, Peter Maydell wrote:
> The *_to_cpup() and cpu_to_*w() functions just compose a pointer
> dereference with a byteswap. Instead use ld*_p() and st*_p(),
> which handle potential pointer misalignment and avoid the need
> to cast the pointer.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> Changes v1->v2: fix cpu_to_*w() uses too.
> 
> The motivation here is that I'd like to get rid of _to_cpup()
> and cpu_to_*w() entirely: we don't have many places that use them.
> ---
>  migration/migration.c | 12 ++++++------
>  migration/savevm.c    |  4 ++--
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 604 bytes --]

Re: [Qemu-devel] [PATCH v2] migration: Don't use *_to_cpup() and cpu_to_*w()

[Amit Shah]

On (Fri) 10 Jun 2016 [17:09:22], Peter Maydell wrote:
> The *_to_cpup() and cpu_to_*w() functions just compose a pointer
> dereference with a byteswap. Instead use ld*_p() and st*_p(),
> which handle potential pointer misalignment and avoid the need
> to cast the pointer.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Amit Shah <amit.shah@redhat.com>

I'll pick this up, thanks.

		Amit