| Message ID | 1424696203-76895-4-git-send-email-agraf@suse.de |
|---|---|
| State | New |
| Headers | show |
* Alexander Graf (agraf@suse.de) wrote: > 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 <agraf@suse.de> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> (I'm leaving 2/3 for someone more familiar with -machine) Dave > --- > 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 38b42b0..35bc377 100644 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@ -332,6 +332,7 @@ 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 63027ee..1305eb0 100644 > --- a/hw/i386/pc_q35.c > +++ b/hw/i386/pc_q35.c > @@ -311,6 +311,7 @@ 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) > -- > 1.7.12.4 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index 38b42b0..35bc377 100644 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@ -332,6 +332,7 @@ 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 63027ee..1305eb0 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -311,6 +311,7 @@ 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)
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 <agraf@suse.de> --- hw/i386/pc_piix.c | 1 + hw/i386/pc_q35.c | 1 + 2 files changed, 2 insertions(+)