From bd3bcf6962b664ca3bf9c60fdcc4534e8e3d0641 Mon Sep 17 00:00:00 2001 From: Xiaoyao Li Date: Wed, 20 Mar 2024 03:39:11 -0500 Subject: [PATCH] kvm/memory: Make memory type private by default if it has guest memfd backend KVM side leaves the memory to shared by default, which may incur the overhead of paging conversion on the first visit of each page. Because the expectation is that page is likely to private for the VMs that require private memory (has guest memfd). Explicitly set the memory to private when memory region has valid guest memfd backend. Signed-off-by: Xiaoyao Li Signed-off-by: Michael Roth Message-ID: <20240320083945.991426-16-michael.roth@amd.com> Signed-off-by: Paolo Bonzini --- accel/kvm/kvm-all.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 0386d4901fa..f49b2b95b54 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -1431,6 +1431,16 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml, strerror(-err)); abort(); } + + if (memory_region_has_guest_memfd(mr)) { + err = kvm_set_memory_attributes_private(start_addr, slot_size); + if (err) { + error_report("%s: failed to set memory attribute private: %s", + __func__, strerror(-err)); + exit(1); + } + } + start_addr += slot_size; ram_start_offset += slot_size; ram += slot_size; -- 2.39.5