diff mbox series

[v5,10/65] kvm/memory: Make memory type private by default if it has guest memfd backend

Message ID 20240229063726.610065-11-xiaoyao.li@intel.com (mailing list archive)
State New, archived
Headers show
Series QEMU Guest memfd + QEMU TDX support | expand

Commit Message

Xiaoyao Li Feb. 29, 2024, 6:36 a.m. UTC 
KVM side leaves the memory to shared by default, while 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 <xiaoyao.li@intel.com>
---
 accel/kvm/kvm-all.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index fe2eb3f06902..0c0719a0303c 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1451,6 +1451,16 @@  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\n",
+                             __func__, strerror(-err));
+                exit(1);
+            }
+        }
+
         start_addr += slot_size;
         ram_start_offset += slot_size;
         ram += slot_size;