From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46219) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gMY0y-0008EG-9N for qemu-devel@nongnu.org; Tue, 13 Nov 2018 07:41:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gMY0v-0004XX-2l for qemu-devel@nongnu.org; Tue, 13 Nov 2018 07:41:56 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58118) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gMY0u-0004Ep-Q0 for qemu-devel@nongnu.org; Tue, 13 Nov 2018 07:41:52 -0500 References: <20181023152306.3123-1-david@redhat.com> <20181023152306.3123-8-david@redhat.com> <20181113132614.3abdaa12@redhat.com> From: David Hildenbrand Message-ID: <9ba9e9af-d544-bc1b-4def-a876917116ee@redhat.com> Date: Tue, 13 Nov 2018 13:41:07 +0100 MIME-Version: 1.0 In-Reply-To: <20181113132614.3abdaa12@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v3 7/7] memory-device: rewrite address assignment using ranges List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: qemu-devel@nongnu.org, Eduardo Habkost , "Michael S . Tsirkin" , Michael Roth , Markus Armbruster , "Dr . David Alan Gilbert" , David Gibson On 13.11.18 13:26, Igor Mammedov wrote: > On Tue, 23 Oct 2018 17:23:06 +0200 > David Hildenbrand wrote: >=20 >> Let's rewrite it properly using ranges. This fixes certain overflows t= hat >> are right now possible. E.g. >> >> qemu-system-x86_64 -m 4G,slots=3D20,maxmem=3D40G -M pc \ >> -object memory-backend-file,id=3Dmem1,share,mem-path=3D/dev/zero,s= ize=3D2G >> -device pc-dimm,memdev=3Dmem1,id=3Ddimm1,addr=3D-0x40000000 >> >> Now properly reports an error instead of succeeding. > s/error/error out/ Thanks, fixed. >=20 >> >> "can't add memory device [0xffffffffc0000000:0x80000000], range overfl= ow" >> >> Signed-off-by: David Hildenbrand >> --- >> 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(Machin= eState *ms, >> uint64_t align, uint64_t = size, >> Error **errp) >> { >> - uint64_t address_space_start, address_space_end; >> GSList *list =3D NULL, *item; >> - uint64_t new_addr =3D 0; >> + Range as, new =3D range_empty; >> =20 >> if (!ms->device_memory) { >> error_setg(errp, "memory devices (e.g. for memory hotplug) ar= e not " >> @@ -115,13 +114,11 @@ static uint64_t memory_device_get_free_addr(Mach= ineState *ms, >> "enabled, please specify the maxmem option")= ; >> return 0; >> } >> - address_space_start =3D ms->device_memory->base; >> - address_space_end =3D address_space_start + >> - memory_region_size(&ms->device_memory->mr); >> - g_assert(address_space_end >=3D address_space_start); >> + range_init_nofail(&as, ms->device_memory->base, >> + memory_region_size(&ms->device_memory->mr)); >> =20 >> - /* 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 expe= ct */ >> + if (!QEMU_IS_ALIGNED(range_lob(&as), align)) { >> error_setg(errp, "the alignment (0x%" PRIx64 ") is not suppor= ted", >> align); >> return 0; >> @@ -145,20 +142,24 @@ static uint64_t memory_device_get_free_addr(Mach= ineState *ms, >> } >> =20 >> if (hint) { >> - new_addr =3D *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%" PRIx= 64 ":0x%" >> + PRIx64 "]", range_lob(&new), range_size(&new), >> + range_lob(&as), range_size(&as)); >> return 0; >> } >> } else { >> - new_addr =3D 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 us= er friendly=20 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. >=20 >> + return 0; >> + } >> } >> =20 >> /* find address range that will fit new memory device */ >> @@ -166,30 +167,36 @@ static uint64_t memory_device_get_free_addr(Mach= ineState *ms, >> for (item =3D list; item; item =3D g_slist_next(item)) { >> const MemoryDeviceState *md =3D item->data; >> const MemoryDeviceClass *mdc =3D MEMORY_DEVICE_GET_CLASS(OBJE= CT(md)); >> - uint64_t md_size, md_addr; >> + uint64_t next_addr; >> + Range tmp; >> =20 >> - md_addr =3D mdc->get_addr(md); >> - md_size =3D memory_device_get_region_size(md, &error_abort); >> + range_init_nofail(&tmp, mdc->get_addr(md), >> + memory_device_get_region_size(md, &error_ab= ort)); >> =20 >> - if (ranges_overlap(md_addr, md_size, new_addr, size)) { >> + if (range_overlaps_range(&tmp, &new)) { >> if (hint) { >> const DeviceState *d =3D DEVICE(md); >> error_setg(errp, "address range conflicts with memory= device" >> " id=3D'%s'", d->id ? d->id : "(unnamed)")= ; >> goto out; >> } >> - new_addr =3D QEMU_ALIGN_UP(md_addr + md_size, align); >> + >> + next_addr =3D QEMU_ALIGN_UP(range_upb(&tmp) + 1, align); > ^^^^^^^^^^^^^^^^^^^ > this theoretically could overflow and already past 'as' check so it wou= ld > return an invalid address without erroring out. >=20 > But in practice we don't have memory device container ending right on 6= 4bit > limit, so it's not really an issue. I'll add a simple check for "!next_addr". >=20 >=20 >> + if (range_init(&new, next_addr, range_size(&new))) { >> + range_make_empty(&new); >> + break; >> + } >> } >> } >> =20 >> - if (new_addr + size > address_space_end) { >> + if (!range_contains_range(&as, &new)) { >> error_setg(errp, "could not find position in guest address sp= ace for " >> "memory device - memory fragmented due to alignmen= ts"); >> goto out; >> } >> out: >> g_slist_free(list); >> - return new_addr; >> + return range_lob(&new); >> } >> =20 >> MemoryDeviceInfoList *qmp_memory_device_list(void) >=20 > beside minor notes patch looks good >=20 Thanks! --=20 Thanks, David / dhildenb