From 2fde3fb916079ee0ff0fc26d9446c813b1d5cc28 Mon Sep 17 00:00:00 2001 From: Chenyi Qiang Date: Thu, 12 Jun 2025 16:27:46 +0800 Subject: physmem: Support coordinated discarding of RAM with guest_memfd A new field, attributes, was introduced in RAMBlock to link to a RamBlockAttributes object, which centralizes all guest_memfd related information (such as fd and status bitmap) within a RAMBlock. Create and initialize the RamBlockAttributes object upon ram_block_add(). Meanwhile, register the object in the target RAMBlock's MemoryRegion. After that, guest_memfd-backed RAMBlock is associated with the RamDiscardManager interface, and the users can execute RamDiscardManager specific handling. For example, VFIO will register the RamDiscardListener and get notifications when the state_change() helper invokes. As coordinate discarding of RAM with guest_memfd is now supported, only block uncoordinated discard. Tested-by: Alexey Kardashevskiy Reviewed-by: Alexey Kardashevskiy Acked-by: David Hildenbrand Signed-off-by: Chenyi Qiang Link: https://lore.kernel.org/r/20250612082747.51539-6-chenyi.qiang@intel.com Signed-off-by: Peter Xu --- accel/kvm/kvm-all.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'accel/kvm/kvm-all.c') diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index a31778341c..d095d1b98f 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -3091,6 +3091,15 @@ int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private) addr = memory_region_get_ram_ptr(mr) + section.offset_within_region; rb = qemu_ram_block_from_host(addr, false, &offset); + ret = ram_block_attributes_state_change(RAM_BLOCK_ATTRIBUTES(mr->rdm), + offset, size, to_private); + if (ret) { + error_report("Failed to notify the listener the state change of " + "(0x%"HWADDR_PRIx" + 0x%"HWADDR_PRIx") to %s", + start, size, to_private ? "private" : "shared"); + goto out_unref; + } + if (to_private) { if (rb->page_size != qemu_real_host_page_size()) { /* -- cgit 1.4.1