Re: [Qemu-devel] [PATCH v4 05/11] target-i386: Remove underscores from property names

[Jiri Denemark]

On Thu, Sep 29, 2016 at 18:14:53 -0300, Eduardo Habkost wrote:
> Instead of translating the feature name entries when adding
> property names, store the actual property names in the feature
> name array.
> 
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
> Changes series v3 -> v4:
> * New patch added to series
> ---
>  target-i386/cpu.c | 31 ++++++++++++++++---------------
>  1 file changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 4eaec0e..7795a7c 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -279,11 +279,11 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] 
> = {
>      [FEAT_1_ECX] = {
>          .feat_names = {
>              "pni|sse3" /* Intel,AMD sse3 */, "pclmulqdq|pclmuldq", "dtes64", 
> "monitor",
> -            "ds_cpl", "vmx", "smx", "est",
> +            "ds-cpl", "vmx", "smx", "est",
>              "tm2", "ssse3", "cid", NULL,
>              "fma", "cx16", "xtpr", "pdcm",
> -            NULL, "pcid", "dca", "sse4.1|sse4_1",
> -            "sse4.2|sse4_2", "x2apic", "movbe", "popcnt",
> +            NULL, "pcid", "dca", "sse4.1|sse4-1",
> +            "sse4.2|sse4-2", "x2apic", "movbe", "popcnt",
>              "tsc-deadline", "aes", "xsave", "osxsave",
>              "avx", "f16c", "rdrand", "hypervisor",
>          },

It wasn't quite obvious to me where this means we can't use the names
with underscores when talking to QEMU. So I tried it and apparently
underscores are just silently translated to dashes. It's backward
compatible this way. However, QEMU will always give us the names with
dashes, which means we have even more differences between libvirt's
feature names and QEMU's feature names. So assuming we'll have an
interface for querying supported CPU properties (and their aliases),
shouldn't the old underscore names be added as aliases? This way, we
could actually know that "ds-cpl" means "ds_cpl".

Jirka