From c53b7ddc61198c4af8290d6310592e48e3507c47 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Thu, 5 Nov 2015 18:11:12 +0000 Subject: [PATCH] postcopy: Check order of received target pages Ensure that target pages received within a host page are in order. This shouldn't trigger, but in the cases where the sender goes wrong and sends stuff out of order it produces a corruption that's really nasty to debug. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- migration/ram.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/migration/ram.c b/migration/ram.c index af5f3692fb..8bf0841fad 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2097,6 +2097,7 @@ static int ram_load_postcopy(QEMUFile *f) MigrationIncomingState *mis = migration_incoming_get_current(); /* Temporary page that is later 'placed' */ void *postcopy_host_page = postcopy_get_tmp_page(mis); + void *last_host = NULL; while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) { ram_addr_t addr; @@ -2133,8 +2134,17 @@ static int ram_load_postcopy(QEMUFile *f) /* If all TP are zero then we can optimise the place */ if (!((uintptr_t)host & ~qemu_host_page_mask)) { all_zero = true; + } else { + /* not the 1st TP within the HP */ + if (host != (last_host + TARGET_PAGE_SIZE)) { + error_report("Non-sequential target page %p/%p\n", + host, last_host); + ret = -EINVAL; + break; + } } + /* * If it's the last part of a host page then we place the host * page @@ -2143,6 +2153,7 @@ static int ram_load_postcopy(QEMUFile *f) ~qemu_host_page_mask) == 0; place_source = postcopy_host_page; } + last_host = host; switch (flags & ~RAM_SAVE_FLAG_CONTINUE) { case RAM_SAVE_FLAG_COMPRESS: