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Re: [PATCH v1 4/5] memory-device: Add get_min_alignment() callback
From: |
Pankaj Gupta |
Subject: |
Re: [PATCH v1 4/5] memory-device: Add get_min_alignment() callback |
Date: |
Sat, 26 Sep 2020 23:07:20 +0200 |
> Will be used by virtio-mem to express special alignment requirements due
> to manually configured, big block sizes. This avoids failing later when
> realizing, because auto-detection wasn't able to assign a properly
> aligned address.
>
> 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 | 11 +++++++++--
> include/hw/mem/memory-device.h | 11 +++++++++++
> 2 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c
> index 8a736f1a26..cf0627fd01 100644
> --- a/hw/mem/memory-device.c
> +++ b/hw/mem/memory-device.c
> @@ -259,7 +259,7 @@ void memory_device_pre_plug(MemoryDeviceState *md,
> MachineState *ms,
> {
> const MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(md);
> Error *local_err = NULL;
> - uint64_t addr, align;
> + uint64_t addr, align = 0;
> MemoryRegion *mr;
>
> mr = mdc->get_memory_region(md, &local_err);
> @@ -267,7 +267,14 @@ void memory_device_pre_plug(MemoryDeviceState *md,
> MachineState *ms,
> goto out;
> }
>
> - align = legacy_align ? *legacy_align : memory_region_get_alignment(mr);
> + if (legacy_align) {
> + align = *legacy_align;
> + } else {
> + if (mdc->get_min_alignment) {
> + align = mdc->get_min_alignment(md);
> + }
> + align = MAX(align, memory_region_get_alignment(mr));
> + }
> addr = mdc->get_addr(md);
> addr = memory_device_get_free_addr(ms, !addr ? NULL : &addr, align,
> memory_region_size(mr), &local_err);
> diff --git a/include/hw/mem/memory-device.h b/include/hw/mem/memory-device.h
> index cde52e83c9..563893854a 100644
> --- a/include/hw/mem/memory-device.h
> +++ b/include/hw/mem/memory-device.h
> @@ -88,6 +88,17 @@ struct MemoryDeviceClass {
> */
> MemoryRegion *(*get_memory_region)(MemoryDeviceState *md, Error **errp);
>
> + /*
> + * Optional: Return the desired minimum alignment of the device in guest
> + * physical address space, ignoring the alignment requirements of the
> + * memory region (e.g., based on the page size). The final alignment is
> + * computed by selecting the maximum of both alignments.
> + *
> + * Called when plugging the memory device to detect the required
> alignment
> + * during address assignment.
> + */
> + uint64_t (*get_min_alignment)(const MemoryDeviceState *md);
> +
> /*
> * Translate the memory device into #MemoryDeviceInfo.
> */
> --
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
- [PATCH v1 4/5] memory-device: Add get_min_alignment() callback, David Hildenbrand, 2020/09/23
- Re: [PATCH v1 4/5] memory-device: Add get_min_alignment() callback,
Pankaj Gupta <=
- [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