[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v2 3/3] pc: Disable vmdesc submission for old ma
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v2 3/3] pc: Disable vmdesc submission for old machines |
Date: |
Wed, 4 Mar 2015 11:53:19 +0000 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
* Alexander Graf (address@hidden) 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 <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
(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 / address@hidden / Manchester, UK
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- Re: [Qemu-devel] [PATCH v2 3/3] pc: Disable vmdesc submission for old machines,
Dr. David Alan Gilbert <=