Kvm | inetshell

Mount a qcow2 disk on the host with qemu-nbd (read or repair files of a powered-off VM)

modprobe nbd max_part=16; qemu-nbd -c /dev/nbd0 vm.qcow2; partprobe; mount /dev/nbd0p1. When done, umount and qemu-nbd -d, or the VM will not start because of the lock. VM off, always; -r to only read.

PiKVM: force 1080p (or any mode you want) by editing the EDID

rw; kvmd-edidconf –import-preset=v3.1080p-by-default –apply; ro; then reboot the host (or replug the HDMI) so it re-reads the EDID. On V4 Mini/Plus none of this is needed: they already do 1080p60.

Proxmox: Windows is slow with CPU type host (md_clear and flush_l1d)

host exposes md_clear and flush_l1d; Windows sees them and enables mitigations that multiply RAM latency (100 ns → 2000 ns on old Xeons). x86-64-v2-AES or v3 do not expose them. qm set –cpu and stop/start.

Virtualized pfSense with VirtIO: no traffic until hardware checksum offload is disabled

With vtnet, FreeBSD drops packets whose checksum was never computed. Tick Disable hardware checksum offload and reboot the VM even though the GUI does not ask; until then no traffic flows.