From 81b0ed8ad81a9e454ffb77ce028e5081b8b3022f Mon Sep 17 00:00:00 2001 From: Fabiano Rosas Date: Wed, 28 Aug 2024 11:56:47 -0300 Subject: [PATCH] migration/multifd: Stop changing the packet on recv side MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As observed by Philippe, the multifd_ram_unfill_packet() function currently leaves the MultiFDPacket structure with mixed endianness. This is harmless, but ultimately not very clean. Stop touching the received packet and do the necessary work using stack variables instead. While here tweak the error strings and fix the space before semicolons. Also remove the "100 times bigger" comment because it's just one possible explanation for a size mismatch and it doesn't even match the code. CC: Philippe Mathieu-Daudé Reviewed-by: Peter Xu Signed-off-by: Fabiano Rosas --- migration/multifd-nocomp.c | 29 ++++++++++++----------------- migration/multifd.c | 20 +++++++++----------- 2 files changed, 21 insertions(+), 28 deletions(-) diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c index f294d1b0b2..07c63f4a72 100644 --- a/migration/multifd-nocomp.c +++ b/migration/multifd-nocomp.c @@ -220,33 +220,28 @@ int multifd_ram_unfill_packet(MultiFDRecvParams *p, Error **errp) MultiFDPacket_t *packet = p->packet; uint32_t page_count = multifd_ram_page_count(); uint32_t page_size = multifd_ram_page_size(); + uint32_t pages_per_packet = be32_to_cpu(packet->pages_alloc); int i; - packet->pages_alloc = be32_to_cpu(packet->pages_alloc); - /* - * If we received a packet that is 100 times bigger than expected - * just stop migration. It is a magic number. - */ - if (packet->pages_alloc > page_count) { - error_setg(errp, "multifd: received packet " - "with size %u and expected a size of %u", - packet->pages_alloc, page_count) ; + if (pages_per_packet > page_count) { + error_setg(errp, "multifd: received packet with %u pages, expected %u", + pages_per_packet, page_count); return -1; } p->normal_num = be32_to_cpu(packet->normal_pages); - if (p->normal_num > packet->pages_alloc) { - error_setg(errp, "multifd: received packet " - "with %u normal pages and expected maximum pages are %u", - p->normal_num, packet->pages_alloc) ; + if (p->normal_num > pages_per_packet) { + error_setg(errp, "multifd: received packet with %u non-zero pages, " + "which exceeds maximum expected pages %u", + p->normal_num, pages_per_packet); return -1; } p->zero_num = be32_to_cpu(packet->zero_pages); - if (p->zero_num > packet->pages_alloc - p->normal_num) { - error_setg(errp, "multifd: received packet " - "with %u zero pages and expected maximum zero pages are %u", - p->zero_num, packet->pages_alloc - p->normal_num) ; + if (p->zero_num > pages_per_packet - p->normal_num) { + error_setg(errp, + "multifd: received packet with %u zero pages, expected maximum %u", + p->zero_num, pages_per_packet - p->normal_num); return -1; } diff --git a/migration/multifd.c b/migration/multifd.c index b89715fdc2..2a8cd9174c 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -230,22 +230,20 @@ void multifd_send_fill_packet(MultiFDSendParams *p) static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp) { - MultiFDPacket_t *packet = p->packet; + const MultiFDPacket_t *packet = p->packet; + uint32_t magic = be32_to_cpu(packet->magic); + uint32_t version = be32_to_cpu(packet->version); int ret = 0; - packet->magic = be32_to_cpu(packet->magic); - if (packet->magic != MULTIFD_MAGIC) { - error_setg(errp, "multifd: received packet " - "magic %x and expected magic %x", - packet->magic, MULTIFD_MAGIC); + if (magic != MULTIFD_MAGIC) { + error_setg(errp, "multifd: received packet magic %x, expected %x", + magic, MULTIFD_MAGIC); return -1; } - packet->version = be32_to_cpu(packet->version); - if (packet->version != MULTIFD_VERSION) { - error_setg(errp, "multifd: received packet " - "version %u and expected version %u", - packet->version, MULTIFD_VERSION); + if (version != MULTIFD_VERSION) { + error_setg(errp, "multifd: received packet version %u, expected %u", + version, MULTIFD_VERSION); return -1; }