On 13.11.18 13:26, Igor Mammedov wrote: > On Tue, 23 Oct 2018 17:23:06 +0200 > 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 reports an error instead of succeeding. > s/error/error out/
Thanks, fixed. > >> >> "can't add memory device [0xffffffffc0000000:0x80000000], range overflow" >> >> Signed-off-by: David Hildenbrand <da...@redhat.com> >> --- >> hw/mem/memory-device.c | 53 ++++++++++++++++++++++++------------------ >> 1 file changed, 30 insertions(+), 23 deletions(-) >> >> diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c >> index 8be63c8032..2fb6fc2145 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 +142,24 @@ 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)) { >> error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" >> PRIx64 >> - "] before 0x%" PRIx64, new_addr, size, >> - address_space_start); >> + "], range overflow", *hint, size); >> return 0; >> - } else if ((new_addr + size) > address_space_end) { >> + } >> + if (!range_contains_range(&as, &new)) { >> 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 "]", range_lob(&new), range_size(&new), >> + 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 [0x%" PRIx64 ":0x%" >> PRIx64 >> + "], range overflow", *hint, size); > maybe replace "range overflow" with "too big" or something else more user > friendly I guess I'll use the same error message for these two cases "can't add memory device [...], usable range for memory devices [...]" That will include the "range overflow" scenario when a hint was given. > >> + return 0; >> + } >> } >> >> /* find address range that will fit new memory device */ >> @@ -166,30 +167,36 @@ 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); > ^^^^^^^^^^^^^^^^^^^ > this theoretically could overflow and already past 'as' check so it would > return an invalid address without erroring out. > > But in practice we don't have memory device container ending right on 64bit > limit, so it's not really an issue. I'll add a simple check for "!next_addr". > > >> + if (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) > > beside minor notes patch looks good > Thanks! -- Thanks, David / dhildenb