Re: [PATCH v2] target/i386: Add Snowridge-v2 (noMPX) CPU model

[Eduardo Habkost]

On Fri, Oct 11, 2019 at 10:53:49PM +0800, Xiaoyao Li wrote:
> Add new version of Snowridge CPU model that removes MPX feature.
> 
> MPX support is being phased out by Intel. GCC has dropped it, Linux kernel
> and kvm are also going to do that in the future.
> 
> Signed-off-by: Xiaoyao Li <address@hidden>
> ---
> Changes in v2:
>     - Use CPU model versioning mechanism instead of machine-type compat
> ---
>  target/i386/cpu.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 44f1bbdcac76..27b0a17b46a8 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -2793,6 +2793,19 @@ static X86CPUDefinition builtin_x86_defs[] = {
>              CPUID_6_EAX_ARAT,
>          .xlevel = 0x80000008,
>          .model_id = "Intel Atom Processor (SnowRidge)",
> +        .versions = (X86CPUVersionDefinition[]) {
> +            { .version = 1 },
> +            {
> +                .version = 2,
> +                .alias = "Snowridge-noMPX",

The intention is to stop creating new funny names for CPU model
variations, now, and stick to -v1, -v2, -v3, etc.

The .alias field is optional, and was added only for
compatibility with the existing -noTSX and -IBRS CPU models.


> +                .props = (PropValue[]) {
> +                    { "mpx", "off" },
> +                    { "model-id", "Intel Atom Processor (Snowridge, no MPX)" 
> },

Do you think it's important to report a different model-id?
I would keep it the same and only add mpx=off.

> +                    { /* end of list */ },
> +                },
> +            },
> +            { /* end of list */ },
> +        },
>      },
>      {
>          .name = "KnightsMill",
> -- 
> 2.19.1
> 

-- 
Eduardo