On Fri, 14 Dec 2018 14:10:43 +0100 David Hildenbrand <da...@redhat.com> wrote:
> 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 <da...@redhat.com> Reviewed-by: Igor Mammedov <imamm...@redhat.com> > --- > 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)