From c726aa69419ba2ecd38ae14dc62aaa189c3510e5 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 8 Oct 2020 10:30:28 +0200 Subject: [PATCH] memory-device: Add get_min_alignment() callback Add a callback that can be used to express additional alignment requirements (exceeding the ones from the memory region). Will be used by virtio-mem to express special alignment requirements due to manually configured, big block sizes (e.g., 1GB with an ordinary memory-backend-ram). This avoids failing later when realizing, because auto-detection wasn't able to assign a properly aligned address. Reviewed-by: Pankaj Gupta Cc: "Michael S. Tsirkin" Cc: Wei Yang Cc: Dr. David Alan Gilbert Cc: Igor Mammedov Cc: Pankaj Gupta Signed-off-by: David Hildenbrand Message-Id: <20201008083029.9504-6-david@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/mem/memory-device.c | 11 +++++++++-- include/hw/mem/memory-device.h | 10 ++++++++++ 2 files changed, 19 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 30d7e99f52..48d2611fc5 100644 --- a/include/hw/mem/memory-device.h +++ b/include/hw/mem/memory-device.h @@ -88,6 +88,16 @@ struct MemoryDeviceClass { */ MemoryRegion *(*get_memory_region)(MemoryDeviceState *md, Error **errp); + /* + * Optional: Return the desired minimum alignment of the device in guest + * physical address space. The final alignment is computed based on this + * alignment and the alignment requirements of the memory region. + * + * 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. */