From e3213eb5ecd541f182e1a5a719feed99d6b225af Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 14 Dec 2018 14:10:43 +0100 Subject: [PATCH] memory-device: rewrite address assignment using ranges Let's rewrite it properly using ranges. This fixes certain overflows that are right now possible. E.g. qemu-system-x86_64 -m 4G,slots=20,maxmem=40G -M pc \ -object memory-backend-file,id=mem1,share,mem-path=/dev/zero,size=2G -device pc-dimm,memdev=mem1,id=dimm1,addr=-0x40000000 Now properly errors out instead of succeeding. (Note that qapi parsing of huge uint64_t values is broken and fixes are on the way) "can't add memory device [0xffffffffa0000000:0x80000000], usable range for memory devices [0x140000000:0xe00000000]" Signed-off-by: David Hildenbrand Message-Id: <20181214131043.25071-3-david@redhat.com> Reviewed-by: Igor Mammedov Reviewed-by: Michael S. Tsirkin Signed-off-by: Eduardo Habkost --- hw/mem/memory-device.c | 51 +++++++++++++++++++++--------------------- 1 file changed, 26 insertions(+), 25 deletions(-) diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c index 8be63c8032..5f2c408036 100644 --- a/hw/mem/memory-device.c +++ b/hw/mem/memory-device.c @@ -100,9 +100,8 @@ static uint64_t memory_device_get_free_addr(MachineState *ms, uint64_t align, uint64_t size, Error **errp) { - uint64_t address_space_start, address_space_end; GSList *list = NULL, *item; - uint64_t new_addr = 0; + Range as, new = range_empty; if (!ms->device_memory) { error_setg(errp, "memory devices (e.g. for memory hotplug) are not " @@ -115,13 +114,11 @@ static uint64_t memory_device_get_free_addr(MachineState *ms, "enabled, please specify the maxmem option"); return 0; } - address_space_start = ms->device_memory->base; - address_space_end = address_space_start + - memory_region_size(&ms->device_memory->mr); - g_assert(address_space_end >= address_space_start); + range_init_nofail(&as, ms->device_memory->base, + memory_region_size(&ms->device_memory->mr)); - /* address_space_start indicates the maximum alignment we expect */ - if (!QEMU_IS_ALIGNED(address_space_start, align)) { + /* start of address space indicates the maximum alignment we expect */ + if (!QEMU_IS_ALIGNED(range_lob(&as), align)) { error_setg(errp, "the alignment (0x%" PRIx64 ") is not supported", align); return 0; @@ -145,20 +142,18 @@ static uint64_t memory_device_get_free_addr(MachineState *ms, } if (hint) { - new_addr = *hint; - if (new_addr < address_space_start) { + if (range_init(&new, *hint, size) || !range_contains_range(&as, &new)) { error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" PRIx64 - "] before 0x%" PRIx64, new_addr, size, - address_space_start); - return 0; - } else if ((new_addr + size) > address_space_end) { - error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" PRIx64 - "] beyond 0x%" PRIx64, new_addr, size, - address_space_end); + "], usable range for memory devices [0x%" PRIx64 ":0x%" + PRIx64 "]", *hint, size, range_lob(&as), + range_size(&as)); return 0; } } else { - new_addr = address_space_start; + if (range_init(&new, range_lob(&as), size)) { + error_setg(errp, "can't add memory device, device too big"); + return 0; + } } /* find address range that will fit new memory device */ @@ -166,30 +161,36 @@ static uint64_t memory_device_get_free_addr(MachineState *ms, for (item = list; item; item = g_slist_next(item)) { const MemoryDeviceState *md = item->data; const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(OBJECT(md)); - uint64_t md_size, md_addr; + uint64_t next_addr; + Range tmp; - md_addr = mdc->get_addr(md); - md_size = memory_device_get_region_size(md, &error_abort); + range_init_nofail(&tmp, mdc->get_addr(md), + memory_device_get_region_size(md, &error_abort)); - if (ranges_overlap(md_addr, md_size, new_addr, size)) { + if (range_overlaps_range(&tmp, &new)) { if (hint) { const DeviceState *d = DEVICE(md); error_setg(errp, "address range conflicts with memory device" " id='%s'", d->id ? d->id : "(unnamed)"); goto out; } - new_addr = QEMU_ALIGN_UP(md_addr + md_size, align); + + next_addr = QEMU_ALIGN_UP(range_upb(&tmp) + 1, align); + if (!next_addr || range_init(&new, next_addr, range_size(&new))) { + range_make_empty(&new); + break; + } } } - if (new_addr + size > address_space_end) { + if (!range_contains_range(&as, &new)) { error_setg(errp, "could not find position in guest address space for " "memory device - memory fragmented due to alignments"); goto out; } out: g_slist_free(list); - return new_addr; + return range_lob(&new); } MemoryDeviceInfoList *qmp_memory_device_list(void) -- GitLab