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Re: [Qemu-devel] [PATCH v5 2/2] memory-device: rewrite address assignmen
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH v5 2/2] memory-device: rewrite address assignment using ranges |
Date: |
Mon, 17 Dec 2018 09:00:59 +0100 |
On Fri, 14 Dec 2018 14:10:43 +0100
David Hildenbrand <address@hidden> 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 <address@hidden>
Reviewed-by: Igor Mammedov <address@hidden>
> ---
> 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)