From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33161) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gXSIa-0007yY-0c for qemu-devel@nongnu.org; Thu, 13 Dec 2018 09:49:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gXSIT-0005r1-Mv for qemu-devel@nongnu.org; Thu, 13 Dec 2018 09:49:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54964) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gXSIT-0005Li-CT for qemu-devel@nongnu.org; Thu, 13 Dec 2018 09:49:05 -0500 Date: Thu, 13 Dec 2018 15:48:38 +0100 From: Igor Mammedov Message-ID: <20181213154838.5c7af97a@redhat.com> In-Reply-To: <0ba15f35-4827-f6f9-7a62-94a13027c727@redhat.com> References: <20181212092821.18260-1-david@redhat.com> <20181212092821.18260-3-david@redhat.com> <20181213132850.2b79d12f@redhat.com> <0ba15f35-4827-f6f9-7a62-94a13027c727@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v4 2/2] memory-device: rewrite address assignment using ranges List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Hildenbrand Cc: qemu-devel@nongnu.org, "Michael S . Tsirkin" , David Gibson , Eduardo Habkost , "Dr . David Alan Gilbert" On Thu, 13 Dec 2018 13:35:28 +0100 David Hildenbrand wrote: > On 13.12.18 13:28, Igor Mammedov wrote: > > On Wed, 12 Dec 2018 10:28:21 +0100 > > David Hildenbrand 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 > >> --- > >> hw/mem/memory-device.c | 54 ++++++++++++++++++++++++------------------ > >> 1 file changed, 31 insertions(+), 23 deletions(-) > >> > >> diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c > >> index 8be63c8032..28e871f562 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 +142,25 @@ 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); > >> + "], usable range for memory devices [0x%" PRIx64 ":0x%" > >> + PRIx64 "]", *hint, size, range_lob(&as), > >> + range_size(&as)); > > this changes error message to be the same as the next one and looses 'before' meaning > > so if you'd like to have the same error message, then prbably merging both branches would be better. > > I can do that, but I'll have to refer to "*hint" and "size" then instead > of range_lob(&new) and range_size(&new), because the range might not be > initialized. either that or better make errors different to avoid confusion. [...] > >> - 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"); > > it could happen due to fragmentation but also in case remaining free space is no enough > > That should be handled via memory_device_check_addable(), which is > called at the beginning of the function. It checks for general size > availability. I've meant AS_LOB AS_UPB 100 1000 MEM1_LOB MEM1_UPB 100 900 then hotplugging MEM2 with size 200 would fail with this message, which could be a bit confusing. Maybe "not enough space to plug device of size %d" would be better? > > Thanks! >