From: Alexander Graf <ag...@suse.de> Older PC machine types might by accident be backwards live migration compatible, but with the new vmdesc self-describing blob in our live migration stream we would break that compatibility.
Also users wouldn't expect massive behaviorial differences when updating to a new version of QEMU while retaining their old machine type, especially not potential breakage in tooling around live migration. So disable vmdesc submission for old PC machine types. Signed-off-by: Alexander Graf <ag...@suse.de> Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com> Signed-off-by: Juan Quintela <quint...@redhat.com> --- hw/i386/pc_piix.c | 1 + hw/i386/pc_q35.c | 1 + 2 files changed, 2 insertions(+) diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index 8eab4ba..36c69d7 100644 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@ -335,6 +335,7 @@ static void pc_compat_2_2(MachineState *machine) CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_RTM, 0); x86_cpu_compat_set_features("Broadwell", FEAT_7_0_EBX, CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_RTM, 0); + machine->suppress_vmdesc = true; } static void pc_compat_2_1(MachineState *machine) diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c index c0f21fe..bc40537 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -314,6 +314,7 @@ static void pc_compat_2_2(MachineState *machine) CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_RTM, 0); x86_cpu_compat_set_features("Broadwell", FEAT_7_0_EBX, CPUID_7_0_EBX_HLE | CPUID_7_0_EBX_RTM, 0); + machine->suppress_vmdesc = true; } static void pc_compat_2_1(MachineState *machine) -- 2.1.0