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Re: [PATCH v1 3/5] memory-device: Support big alignment requirements
From: |
Pankaj Gupta |
Subject: |
Re: [PATCH v1 3/5] memory-device: Support big alignment requirements |
Date: |
Fri, 25 Sep 2020 16:18:48 +0200 |
> Let's warn instead of bailing out - the worst thing that can happen is
> that we'll fail hot/coldplug later. The user got warned, and this should
> be rare.
>
> This will be necessary for memory devices with rather big (user-defined)
> alignment requirements - say a virtio-mem device with a 2G block size -
> which will become important, for example, when supporting vfio in the
> future.
>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Wei Yang <richardw.yang@linux.intel.com>
> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> hw/mem/memory-device.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c
> index 4bc9cf0917..8a736f1a26 100644
> --- a/hw/mem/memory-device.c
> +++ b/hw/mem/memory-device.c
> @@ -119,9 +119,10 @@ static uint64_t memory_device_get_free_addr(MachineState
> *ms,
>
> /* 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;
> + warn_report("the alignment (0x%" PRIx64 ") exceeds the expected"
> + " maximum alignment, memory will get fragmented and not"
> + " all 'maxmem' might be usable for memory devices.",
> + align);
> }
>
> memory_device_check_addable(ms, size, &err);
> @@ -151,7 +152,7 @@ static uint64_t memory_device_get_free_addr(MachineState
> *ms,
> return 0;
> }
> } else {
> - if (range_init(&new, range_lob(&as), size)) {
> + if (range_init(&new, QEMU_ALIGN_UP(range_lob(&as), align), size)) {
> error_setg(errp, "can't add memory device, device too big");
> return 0;
> }
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
- [PATCH v1 0/5] virtio-mem: block size and address-assignment optimizations, David Hildenbrand, 2020/09/23
- [PATCH v1 1/5] virtio-mem: Probe THP size to determine default block size, David Hildenbrand, 2020/09/23
- [PATCH v1 2/5] virtio-mem: Check that "memaddr" is multiples of the block size, David Hildenbrand, 2020/09/23
- [PATCH v1 3/5] memory-device: Support big alignment requirements, David Hildenbrand, 2020/09/23
- Re: [PATCH v1 3/5] memory-device: Support big alignment requirements,
Pankaj Gupta <=
- [PATCH v1 4/5] memory-device: Add get_min_alignment() callback, David Hildenbrand, 2020/09/23
- [PATCH v1 5/5] virito-mem: Implement get_min_alignment(), David Hildenbrand, 2020/09/23
- Re: [PATCH v1 0/5] virtio-mem: block size and address-assignment optimizations, David Hildenbrand, 2020/09/25