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migration/ram.c: Avoid taking address of fields in packed MultiFDInit_t struct 

Taking the address of a field in a packed struct is a bad idea, because
it might not be actually aligned enough for that pointer type (and
thus cause a crash on dereference on some host architectures). Newer
versions of clang warn about this:

migration/ram.c:651:19: warning: taking address of packed member 'magic' of class or structure 'MultiFDInit_t' may result in an unaligned pointer value [-Waddress-of-packed-member]
migration/ram.c:652:19: warning: taking address of packed member 'version' of class or structure 'MultiFDInit_t' may result in an unaligned pointer value [-Waddress-of-packed-member]
migration/ram.c:737:19: warning: taking address of packed member 'magic' of class or structure 'MultiFDPacket_t' may result in an unaligned pointer value [-Waddress-of-packed-member]
migration/ram.c:745:19: warning: taking address of packed member 'version' of class or structure 'MultiFDPacket_t' may result in an unaligned pointer value [-Waddress-of-packed-member]
migration/ram.c:755:19: warning: taking address of packed member 'size' of class or structure 'MultiFDPacket_t' may result in an unaligned pointer value [-Waddress-of-packed-member]

Avoid the bug by not using the "modify in place" byteswapping
functions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20180925161924.7832-1-peter.maydell@linaro.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Peter Maydell 2018-09-25 17:19:24 +01:00 committed by Dr. David Alan Gilbert
parent 05306935b1
commit 341ba0df4c
1 changed files with 5 additions and 5 deletions
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10
migration/ram.c
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@ -651,8 +651,8 @@ static int multifd_recv_initial_packet(QIOChannel *c, Error **errp)
return -1;
}
be32_to_cpus(&msg.magic);
be32_to_cpus(&msg.version);
msg.magic = be32_to_cpu(msg.magic);
msg.version = be32_to_cpu(msg.version);
if (msg.magic != MULTIFD_MAGIC) {
error_setg(errp, "multifd: received packet magic %x "
@ -737,7 +737,7 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
RAMBlock *block;
int i;
be32_to_cpus(&packet->magic);
packet->magic = be32_to_cpu(packet->magic);
if (packet->magic != MULTIFD_MAGIC) {
error_setg(errp, "multifd: received packet "
"magic %x and expected magic %x",
@ -745,7 +745,7 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
return -1;
}
be32_to_cpus(&packet->version);
packet->version = be32_to_cpu(packet->version);
if (packet->version != MULTIFD_VERSION) {
error_setg(errp, "multifd: received packet "
"version %d and expected version %d",
@ -755,7 +755,7 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
p->flags = be32_to_cpu(packet->flags);
be32_to_cpus(&packet->size);
packet->size = be32_to_cpu(packet->size);
if (packet->size > migrate_multifd_page_count()) {
error_setg(errp, "multifd: received packet "
"with size %d and expected maximum size %d",