Re: [uq/master PATCH 1/7] target-i386: Eliminate CONFIG_KVM #ifdefs

Paolo Bonzini
2014-01-31T11:42:31Z

Il 30/01/2014 20:48, Eduardo Habkost ha scritto:
> The compiler is already able to eliminate the kvm_arch_get_supported_cpuid()
> calls in kvm_cpu_fill_host() and filter_features_for_kvm(), so we can
> eliminate the CONFIG_KVM #ifdefs there.
>
> Also, kvm_cpu_fill_host() and host_cpuid() don't need to check
> CONFIG_KVM, as they don't have any KVM-specific function calls.
>
> Tested to build successfully with CONFIG_KVM disabled, using the
> following CFLAGS combinations: "-DNDEBUG", "-DNDEBUG -O', "-DNDEBUG
> -O0", "-DNDEBUG -O1", "-DNDEBUG -O2".
>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> Changes v2:
> * Check for __i386__ on host_cpuid() so the code compiles properly
> on non-x86 hosts.
> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
>
> Change v3:
> * Don't add assert(kvm_enabled()) line, which is not necessary to help
> the compiler (and wouldn't help it if using -DNDEBUG, anyway).
> Reported-by: Richard Henderson <rth@twiddle.net>
> * Commit message update
> ---
> target-i386/cpu.c | 15 +++------------
> 1 file changed, 3 insertions(+), 12 deletions(-)
>
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 1f30efd..8425212 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -374,7 +374,6 @@ void disable_kvm_pv_eoi(void)
> void host_cpuid(uint32_t function, uint32_t count,
> uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
> {
> -#if defined(CONFIG_KVM)
> uint32_t vec[4];
>
> #ifdef __x86_64__
> @@ -382,7 +381,7 @@ void host_cpuid(uint32_t function, uint32_t count,
> : "=a"(vec[0]), "=b"(vec[1]),
> "=c"(vec[2]), "=d"(vec[3])
> : "0"(function), "c"(count) : "cc");
> -#else
> +#elif defined(__i386__)
> asm volatile("pusha \n\t"
> "cpuid \n\t"
> "mov %%eax, 0(%2) \n\t"
> @@ -392,6 +391,8 @@ void host_cpuid(uint32_t function, uint32_t count,
> "popa"
> : : "a"(function), "c"(count), "S"(vec)
> : "memory", "cc");
> +#else
> + abort();
> #endif
>
> if (eax)
> @@ -402,7 +403,6 @@ void host_cpuid(uint32_t function, uint32_t count,
> *ecx = vec[2];
> if (edx)
> *edx = vec[3];
> -#endif
> }
>
> #define iswhite(c) ((c) && ((c) <= ' ' || '~' < (c)))
> @@ -1119,7 +1119,6 @@ void x86_cpu_compat_set_features(const char *cpu_model, FeatureWord w,
> }
> }
>
> -#ifdef CONFIG_KVM
> static int cpu_x86_fill_model_id(char *str)
> {
> uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
> @@ -1134,7 +1133,6 @@ static int cpu_x86_fill_model_id(char *str)
> }
> return 0;
> }
> -#endif
>
> /* Fill a x86_def_t struct with information about the host CPU, and
> * the CPU features supported by the host hardware + host kernel
> @@ -1143,7 +1141,6 @@ static int cpu_x86_fill_model_id(char *str)
> */
> static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
> {
> -#ifdef CONFIG_KVM
> KVMState *s = kvm_state;
> uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
>
> @@ -1173,8 +1170,6 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
> kvm_arch_get_supported_cpuid(s, wi->cpuid_eax, wi->cpuid_ecx,
> wi->cpuid_reg);
> }
> -
> -#endif /* CONFIG_KVM */
> }
>
> static int unavailable_host_feature(FeatureWordInfo *f, uint32_t mask)
> @@ -1817,7 +1812,6 @@ CpuDefinitionInfoList *arch_query_cpu_definitions(Error **errp)
> return cpu_list;
> }
>
> -#ifdef CONFIG_KVM
> static void filter_features_for_kvm(X86CPU *cpu)
> {
> CPUX86State *env = &cpu->env;
> @@ -1834,7 +1828,6 @@ static void filter_features_for_kvm(X86CPU *cpu)
> cpu->filtered_features[w] = requested_features & ~env->features[w];
> }
> }
> -#endif
>
> static void cpu_x86_register(X86CPU *cpu, const char *name, Error **errp)
> {
> @@ -2545,9 +2538,7 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
> "Host's CPU doesn't support requested features");
> goto out;
> }
> -#ifdef CONFIG_KVM
> filter_features_for_kvm(cpu);
> -#endif
> }
>
> #ifndef CONFIG_USER_ONLY
>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>