Not only for Windows, nested virtualization with just x86-64-v2-AES and the nested-virt flag does not work on Linux either. While virtualization support is detected, actually starting a nested VM with such a configuration fails. For example, a Proxmox VE/PBS file-restore VM on my test system fails with the following (adding the apic and x2apic flags on top wouldn't make a difference):
[2025-11-19T10:37:44+01:00] PBS file restore VM log ERROR: Unable to locate IOAPIC for GSI 2 ERROR: Unable to locate IOAPIC for GSI 5 ERROR: Unable to locate IOAPIC for GSI 9 ERROR: Unable to locate IOAPIC for GSI 10 ERROR: Unable to locate IOAPIC for GSI 11 ERROR: Unable to locate IOAPIC for GSI 1 ERROR: Unable to locate IOAPIC for GSI 2 ERROR: Unable to locate IOAPIC for GSI 3 ERROR: Unable to locate IOAPIC for GSI 4 ERROR: Unable to locate IOAPIC for GSI 5 ERROR: Unable to locate IOAPIC for GSI 6 ERROR: Unable to locate IOAPIC for GSI 7 ERROR: Unable to locate IOAPIC for GSI 8 ERROR: Unable to locate IOAPIC for GSI 9 ERROR: Unable to locate IOAPIC for GSI 10 ERROR: Unable to locate IOAPIC for GSI 11 ERROR: Unable to locate IOAPIC for GSI 12 ERROR: Unable to locate IOAPIC for GSI 13 ERROR: Unable to locate IOAPIC for GSI 14 ERROR: Unable to locate IOAPIC for GSI 15 ..MP-BIOS bug: 8254 timer not connected to IO-APIC Kernel panic - not syncing: IO-APIC + timer doesn't work! Boot with apic=debug and send a report. Then try booting with the 'noapic' option. CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G W 6.14.6-pbs-restore #1 Tainted: [W]=WARN Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x4a/0x70 panic+0xf5/0x281 ? _printk+0x55/0x60 setup_IO_APIC+0x6ee/0x6f0 ? __ioapic_read_entry+0x23/0x40 ? clear_IO_APIC_pin+0x11e/0x1e0 apic_intr_mode_init+0xad/0xc0 x86_late_time_init+0x12/0x30 start_kernel+0x538/0x5b0 x86_64_start_reservations+0x25/0x30 x86_64_start_kernel+0x73/0x80 common_startup_64+0x129/0x138 </TASK> Reported-by: Lukas Wagner <[email protected]> Signed-off-by: Fiona Ebner <[email protected]> --- src/PVE/QemuServer/CPUConfig.pm | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/PVE/QemuServer/CPUConfig.pm b/src/PVE/QemuServer/CPUConfig.pm index c0d4c9a4..b63743be 100644 --- a/src/PVE/QemuServer/CPUConfig.pm +++ b/src/PVE/QemuServer/CPUConfig.pm @@ -170,7 +170,7 @@ my $supported_cpu_flags = [ name => 'nested-virt', description => "Controls nested virtualization, namely 'svm' for AMD CPUs and 'vmx' for" . " Intel CPUs. Live migration still only works if it's the same flag on both sides." - . " For Windows, use a CPU model similar to the host, with the same vendor!", + . " Use a CPU model similar to the host, with the same vendor, not x86-64-vX!", }, { name => 'md-clear', -- 2.47.3 _______________________________________________ pve-devel mailing list [email protected] https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
