| Message ID | 20181009205652.10605-8-david@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | qapi/range/memory-device: fixes and cleanups | expand |
* David Hildenbrand (david@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. > > "can't add memory device [0xffffffffc0000000:0x80000000], range overflow" > > Signed-off-by: David Hildenbrand <david@redhat.com> > --- > hw/mem/memory-device.c | 56 +++++++++++++++++++++++++----------------- > 1 file changed, 33 insertions(+), 23 deletions(-) > > diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c > index 8be63c8032..1ca9c8e410 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(&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 +142,26 @@ static uint64_t memory_device_get_free_addr(MachineState *ms, > } > > if (hint) { > - new_addr = *hint; > - if (new_addr < address_space_start) { > + if (!range_valid(*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) { > + } > + range_init(&new, *hint, size); > + if (range_starts_before_range(&new, &as)) { > + error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" PRIx64 > + "] before 0x%" PRIx64, range_lob(&new), range_size(&new), > + range_lob(&as)); > + return 0; > + } else if (range_ends_after_range(&new, &as)) { > error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" PRIx64 > - "] beyond 0x%" PRIx64, new_addr, size, > - address_space_end); > + "] beyond 0x%" PRIx64, range_lob(&new), range_size(&new), > + range_upb(&as)); Would !range_contains_range be easier here? > return 0; > } > } else { > - new_addr = address_space_start; > + /* our previous size checks make sure that this never overflows */ Hmm, which one exactly? > + range_init(&new, range_lob(&as), size); > } > > /* find address range that will fit new memory device */ > @@ -166,30 +169,37 @@ 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(&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 (!range_valid(next_addr, size)) { > + range_make_empty(&new); > + break; > + } > + range_init(&new, next_addr, size); > } > } > > - 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) > -- > 2.17.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>> if (hint) { >> - new_addr = *hint; >> - if (new_addr < address_space_start) { >> + if (!range_valid(*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) { >> + } >> + range_init(&new, *hint, size); >> + if (range_starts_before_range(&new, &as)) { >> + error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" PRIx64 >> + "] before 0x%" PRIx64, range_lob(&new), range_size(&new), >> + range_lob(&as)); >> + return 0; >> + } else if (range_ends_after_range(&new, &as)) { >> error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" PRIx64 >> - "] beyond 0x%" PRIx64, new_addr, size, >> - address_space_end); >> + "] beyond 0x%" PRIx64, range_lob(&new), range_size(&new), >> + range_upb(&as)); > > Would !range_contains_range be easier here? Yes, but then we have to change the error message, e.g. to can't add memory device [...:...], usable range [...:...] > >> return 0; >> } >> } else { >> - new_addr = address_space_start; >> + /* our previous size checks make sure that this never overflows */ > > Hmm, which one exactly? Previous patch in this series, via memory_device_check_addable(). But we can add an explicit check here. > >> + range_init(&new, range_lob(&as), size); >> }
diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c index 8be63c8032..1ca9c8e410 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(&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 +142,26 @@ static uint64_t memory_device_get_free_addr(MachineState *ms, } if (hint) { - new_addr = *hint; - if (new_addr < address_space_start) { + if (!range_valid(*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) { + } + range_init(&new, *hint, size); + if (range_starts_before_range(&new, &as)) { + error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" PRIx64 + "] before 0x%" PRIx64, range_lob(&new), range_size(&new), + range_lob(&as)); + return 0; + } else if (range_ends_after_range(&new, &as)) { error_setg(errp, "can't add memory device [0x%" PRIx64 ":0x%" PRIx64 - "] beyond 0x%" PRIx64, new_addr, size, - address_space_end); + "] beyond 0x%" PRIx64, range_lob(&new), range_size(&new), + range_upb(&as)); return 0; } } else { - new_addr = address_space_start; + /* our previous size checks make sure that this never overflows */ + range_init(&new, range_lob(&as), size); } /* find address range that will fit new memory device */ @@ -166,30 +169,37 @@ 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(&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 (!range_valid(next_addr, size)) { + range_make_empty(&new); + break; + } + range_init(&new, next_addr, size); } } - 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)
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. "can't add memory device [0xffffffffc0000000:0x80000000], range overflow" Signed-off-by: David Hildenbrand <david@redhat.com> --- hw/mem/memory-device.c | 56 +++++++++++++++++++++++++----------------- 1 file changed, 33 insertions(+), 23 deletions(-)