From 4d8938a05db15dea2c86c4ab9c5f872f160d2188 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 7 Jun 2018 17:47:04 +0200 Subject: [PATCH] memory-device: turn alignment assert into check The start of the address space indicates which maximum alignment is supported by our machine (e.g. ppc, x86 1GB). This is helpful to catch fragmenting guest physical memory in strange fashions. Right now we can crash QEMU by e.g. (there might be easier examples) qemu-system-x86_64 -m 256M,maxmem=20G,slots=2 \ -object memory-backend-file,id=mem0,size=8192M,mem-path=/dev/zero,align=8192M \ -device pc-dimm,id=dimm1,memdev=mem0 Signed-off-by: David Hildenbrand Message-Id: <20180607154705.6316-2-david@redhat.com> Reviewed-by: Michael S. Tsirkin Reviewed-by: Igor Mammedov Signed-off-by: Paolo Bonzini --- hw/mem/memory-device.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c index 3e04f3954e..6de4f70bb4 100644 --- a/hw/mem/memory-device.c +++ b/hw/mem/memory-device.c @@ -116,9 +116,15 @@ uint64_t memory_device_get_free_addr(MachineState *ms, const uint64_t *hint, address_space_start = ms->device_memory->base; address_space_end = address_space_start + memory_region_size(&ms->device_memory->mr); - g_assert(QEMU_ALIGN_UP(address_space_start, align) == address_space_start); g_assert(address_space_end >= address_space_start); + /* address_space_start indicates the maximum alignment we expect */ + if (QEMU_ALIGN_UP(address_space_start, align) != address_space_start) { + error_setg(errp, "the alignment (0%" PRIx64 ") is not supported", + align); + return 0; + } + memory_device_check_addable(ms, size, errp); if (*errp) { return 0; -- GitLab