On Wed, Jan 09, 2013 at 04:53:42PM -0200, Eduardo Habkost wrote:
> This is a cleanup that tries to solve two small issues:
>
> - We don't need a separate kvm_pv_eoi_features variable just to keep a
> constant calculated at compile-time, and this style would require
> adding a separate variable (that's declared twice because of the
> CONFIG_KVM ifdef) for each feature that's going to be enabled/disable
> by machine-type compat code.
> - The pc-1.3 code is setting the kvm_pv_eoi flag on cpuid_kvm_features
> even when KVM is disabled at runtime. This small incosistency in
> the cpuid_kvm_features field isn't a problem today because
> cpuid_kvm_features is ignored by the TCG code, but it may cause
> unexpected problems later when refactoring the CPUID handling code.
>
> This patch eliminates the kvm_pv_eoi_features variable and simply uses
> kvm_enabled() inside the enable_kvm_pv_eoi() compat function, so it
> enables kvm_pv_eoi only if KVM is enabled. I believe this makes the
> behavior of enable_kvm_pv_eoi() clearer and easier to understand.
>
> Signed-off-by: Eduardo Habkost <ehabkost@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> Cc: kvm@xxxxxxxxxxxxxxx
> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Cc: Gleb Natapov <gleb@xxxxxxxxxx>
> Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
>
> Changes v2:
> - Coding style fix
>
> Changes v3:
> - Eliminate #ifdef by using the fake KVM_FEATURE_PV_EOI #define
>
> Changes v4:
> - Check kvm_enabled() when actually using kvm_default_features
> - Eliminate Yet Another #ifdef by using the fake KVM_FEATURE_*
> #defines on kvm_default_features initialization
> ---
> target-i386/cpu.c | 16 ++++++----------
> 1 file changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index e4dc370..57a22b7 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -206,22 +206,16 @@ typedef struct model_features_t {
> int check_cpuid = 0;
> int enforce_cpuid = 0;
>
> -#if defined(CONFIG_KVM)
> static uint32_t kvm_default_features = (1 << KVM_FEATURE_CLOCKSOURCE) |
> (1 << KVM_FEATURE_NOP_IO_DELAY) |
> (1 << KVM_FEATURE_CLOCKSOURCE2) |
> (1 << KVM_FEATURE_ASYNC_PF) |
> (1 << KVM_FEATURE_STEAL_TIME) |
> (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
> -static const uint32_t kvm_pv_eoi_features = (0x1 << KVM_FEATURE_PV_EOI);
> -#else
> -static uint32_t kvm_default_features = 0;
> -static const uint32_t kvm_pv_eoi_features = 0;
> -#endif
>
> void enable_kvm_pv_eoi(void)
> {
> - kvm_default_features |= kvm_pv_eoi_features;
> + kvm_default_features |= (1UL << KVM_FEATURE_PV_EOI);
> }
>
> void host_cpuid(uint32_t function, uint32_t count,
> @@ -1343,13 +1337,15 @@ static int cpu_x86_parse_featurestr(x86_def_t *x86_cpu_def, char *features)
> unsigned int i;
> char *featurestr; /* Single 'key=value" string being parsed */
> /* Features to be added */
> - FeatureWordArray plus_features = {
> - [FEAT_KVM] = kvm_default_features,
> - };
> + FeatureWordArray plus_features = { 0 };
> /* Features to be removed */
> FeatureWordArray minus_features = { 0 };
> uint32_t numvalue;
>
> + if (kvm_enabled()) {
> + plus_features[FEAT_KVM] = kvm_default_features;
> + }
> +
> add_flagname_to_bitmaps("hypervisor", plus_features);
>
> featurestr = features ? strtok(features, ",") : NULL;
> --
> 1.7.11.7
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