Re: [Qemu-devel] [PATCH 1/3] pc: Set hw_version on all machine classes

[Laszlo Ersek]

On 09/22/15 22:16, Eduardo Habkost wrote:
> In 2012, QEMU had a bug where it exposed QEMU version information to the
> guest, meaning a QEMU upgrade would expose different hardware to the
> guest OS even if the same machine-type is being used.
> 
> The bug was fixed by commit 93bfef4c6e4b23caea9d51e1099d06433d8835a4, on
> all machines up to pc-1.0. But we kept introducing the same bug on all
> newer machines since then. That means we are breaking guest ABI every
> time QEMU was upgraded.
> 
> Fix this by setting the hw_version on all PC machines, making sure the
> hardware won't change when upgrading QEMU.
> 
> Note that QEMU_VERSION was "1.0" in QEMU 1.0, but starting on QEMU
> 1.1.0, it started following the "x.y.0" pattern. We have to follow it,
> to make sure we use the right QEMU_VERSION string from each QEMU
> release.
> 
> The 2.5 machine classes could have hw_version unset, because the default
> value for qemu_get_version() is QEMU_VERSION. But I decided to set it
> explicitly to QEMU_VERSION so we don't forget to update it to "2.5.0"
> after we release 2.5.0 and create a 2.6 machine class.
> 
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
>  hw/i386/pc_piix.c | 13 +++++++++++++
>  hw/i386/pc_q35.c  | 10 ++++++++++
>  2 files changed, 23 insertions(+)
> 
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 3ffb05f..0539467 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -467,6 +467,7 @@ static void pc_i440fx_machine_options(MachineClass *m)
>  static void pc_i440fx_2_5_machine_options(MachineClass *m)
>  {
>      pc_i440fx_machine_options(m);
> +    m->hw_version = QEMU_VERSION;
>      m->alias = "pc";
>      m->is_default = 1;
>  }
> @@ -479,6 +480,7 @@ static void pc_i440fx_2_4_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
>      pc_i440fx_2_5_machine_options(m);
> +    m->hw_version = "2.4.0";
>      m->alias = NULL;
>      m->is_default = 0;
>      pcmc->broken_reserved_end = true;
> @@ -492,6 +494,7 @@ DEFINE_I440FX_MACHINE(v2_4, "pc-i440fx-2.4", NULL,
>  static void pc_i440fx_2_3_machine_options(MachineClass *m)
>  {
>      pc_i440fx_2_4_machine_options(m);
> +    m->hw_version = "2.3.0";
>      m->alias = NULL;
>      m->is_default = 0;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_3);
> @@ -504,6 +507,7 @@ DEFINE_I440FX_MACHINE(v2_3, "pc-i440fx-2.3", 
> pc_compat_2_3,
>  static void pc_i440fx_2_2_machine_options(MachineClass *m)
>  {
>      pc_i440fx_2_3_machine_options(m);
> +    m->hw_version = "2.2.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_2);
>  }
>  
> @@ -514,6 +518,7 @@ DEFINE_I440FX_MACHINE(v2_2, "pc-i440fx-2.2", 
> pc_compat_2_2,
>  static void pc_i440fx_2_1_machine_options(MachineClass *m)
>  {
>      pc_i440fx_2_2_machine_options(m);
> +    m->hw_version = "2.1.0";
>      m->default_display = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_1);
>  }
> @@ -526,6 +531,7 @@ DEFINE_I440FX_MACHINE(v2_1, "pc-i440fx-2.1", 
> pc_compat_2_1,
>  static void pc_i440fx_2_0_machine_options(MachineClass *m)
>  {
>      pc_i440fx_2_1_machine_options(m);
> +    m->hw_version = "2.0.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_0);
>  }
>  
> @@ -536,6 +542,7 @@ DEFINE_I440FX_MACHINE(v2_0, "pc-i440fx-2.0", 
> pc_compat_2_0,
>  static void pc_i440fx_1_7_machine_options(MachineClass *m)
>  {
>      pc_i440fx_2_0_machine_options(m);
> +    m->hw_version = "1.7.0";
>      m->default_machine_opts = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_7);
>  }
> @@ -547,6 +554,7 @@ DEFINE_I440FX_MACHINE(v1_7, "pc-i440fx-1.7", 
> pc_compat_1_7,
>  static void pc_i440fx_1_6_machine_options(MachineClass *m)
>  {
>      pc_i440fx_1_7_machine_options(m);
> +    m->hw_version = "1.6.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_6);
>  }
>  
> @@ -557,6 +565,7 @@ DEFINE_I440FX_MACHINE(v1_6, "pc-i440fx-1.6", 
> pc_compat_1_6,
>  static void pc_i440fx_1_5_machine_options(MachineClass *m)
>  {
>      pc_i440fx_1_6_machine_options(m);
> +    m->hw_version = "1.5.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_5);
>  }
>  
> @@ -567,6 +576,7 @@ DEFINE_I440FX_MACHINE(v1_5, "pc-i440fx-1.5", 
> pc_compat_1_5,
>  static void pc_i440fx_1_4_machine_options(MachineClass *m)
>  {
>      pc_i440fx_1_5_machine_options(m);
> +    m->hw_version = "1.4.0";
>      m->hot_add_cpu = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_4);
>  }
> @@ -599,6 +609,7 @@ DEFINE_I440FX_MACHINE(v1_4, "pc-i440fx-1.4", 
> pc_compat_1_4,
>  static void pc_i440fx_1_3_machine_options(MachineClass *m)
>  {
>      pc_i440fx_1_4_machine_options(m);
> +    m->hw_version = "1.3.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_3);
>  }
>  
> @@ -637,6 +648,7 @@ DEFINE_I440FX_MACHINE(v1_3, "pc-1.3", pc_compat_1_3,
>  static void pc_i440fx_1_2_machine_options(MachineClass *m)
>  {
>      pc_i440fx_1_3_machine_options(m);
> +    m->hw_version = "1.2.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_2);
>  }
>  
> @@ -679,6 +691,7 @@ DEFINE_I440FX_MACHINE(v1_2, "pc-1.2", pc_compat_1_2,
>  static void pc_i440fx_1_1_machine_options(MachineClass *m)
>  {
>      pc_i440fx_1_2_machine_options(m);
> +    m->hw_version = "1.1.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_1);
>  }
>  
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 1b7d3b6..2aa1815 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -373,6 +373,7 @@ static void pc_q35_machine_options(MachineClass *m)
>  static void pc_q35_2_5_machine_options(MachineClass *m)
>  {
>      pc_q35_machine_options(m);
> +    m->hw_version = QEMU_VERSION;
>      m->alias = "q35";
>  }
>  
> @@ -383,6 +384,7 @@ static void pc_q35_2_4_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
>      pc_q35_2_5_machine_options(m);
> +    m->hw_version = "2.4.0";
>      m->alias = NULL;
>      pcmc->broken_reserved_end = true;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_4);
> @@ -395,6 +397,7 @@ DEFINE_Q35_MACHINE(v2_4, "pc-q35-2.4", NULL,
>  static void pc_q35_2_3_machine_options(MachineClass *m)
>  {
>      pc_q35_2_4_machine_options(m);
> +    m->hw_version = "2.3.0";
>      m->no_floppy = 0;
>      m->no_tco = 1;
>      m->alias = NULL;
> @@ -408,6 +411,7 @@ DEFINE_Q35_MACHINE(v2_3, "pc-q35-2.3", pc_compat_2_3,
>  static void pc_q35_2_2_machine_options(MachineClass *m)
>  {
>      pc_q35_2_3_machine_options(m);
> +    m->hw_version = "2.2.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_2);
>  }
>  
> @@ -418,6 +422,7 @@ DEFINE_Q35_MACHINE(v2_2, "pc-q35-2.2", pc_compat_2_2,
>  static void pc_q35_2_1_machine_options(MachineClass *m)
>  {
>      pc_q35_2_2_machine_options(m);
> +    m->hw_version = "2.1.0";
>      m->default_display = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_1);
>  }
> @@ -429,6 +434,7 @@ DEFINE_Q35_MACHINE(v2_1, "pc-q35-2.1", pc_compat_2_1,
>  static void pc_q35_2_0_machine_options(MachineClass *m)
>  {
>      pc_q35_2_1_machine_options(m);
> +    m->hw_version = "2.0.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_0);
>  }
>  
> @@ -439,6 +445,7 @@ DEFINE_Q35_MACHINE(v2_0, "pc-q35-2.0", pc_compat_2_0,
>  static void pc_q35_1_7_machine_options(MachineClass *m)
>  {
>      pc_q35_2_0_machine_options(m);
> +    m->hw_version = "1.7.0";
>      m->default_machine_opts = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_7);
>  }
> @@ -450,6 +457,7 @@ DEFINE_Q35_MACHINE(v1_7, "pc-q35-1.7", pc_compat_1_7,
>  static void pc_q35_1_6_machine_options(MachineClass *m)
>  {
>      pc_q35_machine_options(m);
> +    m->hw_version = "1.6.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_6);
>  }
>  
> @@ -460,6 +468,7 @@ DEFINE_Q35_MACHINE(v1_6, "pc-q35-1.6", pc_compat_1_6,
>  static void pc_q35_1_5_machine_options(MachineClass *m)
>  {
>      pc_q35_1_6_machine_options(m);
> +    m->hw_version = "1.5.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_5);
>  }
>  
> @@ -470,6 +479,7 @@ DEFINE_Q35_MACHINE(v1_5, "pc-q35-1.5", pc_compat_1_5,
>  static void pc_q35_1_4_machine_options(MachineClass *m)
>  {
>      pc_q35_1_5_machine_options(m);
> +    m->hw_version = "1.4.0";
>      m->hot_add_cpu = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_1_4);
>  }
> 

Can you please add:

Reported-by: Laszlo Ersek <address@hidden>

to this patch? (If you agree, that is.)

Other than that, while I'm sure you'll need (and get) other reviews too:

Reviewed-by: Laszlo Ersek <address@hidden>

Thanks
Laszlo