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Re: [Qemu-devel] [PATCH 1/4] target/i386: Use simple static property for
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH 1/4] target/i386: Use simple static property for "model-id" |
Date: |
Mon, 17 Jul 2017 14:03:43 +0200 |
On Wed, 12 Jul 2017 13:20:55 -0300
Eduardo Habkost <address@hidden> wrote:
> Instead of storing the raw CPUID data in CPUX86State and having
> to convert the data back and forth on the QOM getter/setter, use
> a simple static string property, and calculate CPUID data inside
> cpu_x86_cpuid().
wouldn't this slow down 'cpuid' instruction execution,
especially in tcg mode?
Why do you need this patch except of nice code reduction it gives?
>
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
> target/i386/cpu.h | 2 +-
> target/i386/cpu.c | 62
> ++++++++++++++++---------------------------------------
> 2 files changed, 19 insertions(+), 45 deletions(-)
>
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 7a228af..f56a3ea 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -1151,7 +1151,7 @@ typedef struct CPUX86State {
> FeatureWordArray features;
> /* Features that were explicitly enabled/disabled */
> FeatureWordArray user_features;
> - uint32_t cpuid_model[12];
> + char *model_id;
>
> /* MTRRs */
> uint64_t mtrr_fixed[11];
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index c571772..30b704c 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -1828,43 +1828,6 @@ static void x86_cpuid_set_vendor(Object *obj, const
> char *value,
> }
> }
>
> -static char *x86_cpuid_get_model_id(Object *obj, Error **errp)
> -{
> - X86CPU *cpu = X86_CPU(obj);
> - CPUX86State *env = &cpu->env;
> - char *value;
> - int i;
> -
> - value = g_malloc(48 + 1);
> - for (i = 0; i < 48; i++) {
> - value[i] = env->cpuid_model[i >> 2] >> (8 * (i & 3));
> - }
> - value[48] = '\0';
> - return value;
> -}
> -
> -static void x86_cpuid_set_model_id(Object *obj, const char *model_id,
> - Error **errp)
> -{
> - X86CPU *cpu = X86_CPU(obj);
> - CPUX86State *env = &cpu->env;
> - int c, len, i;
> -
> - if (model_id == NULL) {
> - model_id = "";
> - }
> - len = strlen(model_id);
> - memset(env->cpuid_model, 0, 48);
> - for (i = 0; i < 48; i++) {
> - if (i >= len) {
> - c = '\0';
> - } else {
> - c = (uint8_t)model_id[i];
> - }
> - env->cpuid_model[i >> 2] |= c << (8 * (i & 3));
> - }
> -}
> -
> static void x86_cpuid_get_tsc_freq(Object *obj, Visitor *v, const char *name,
> void *opaque, Error **errp)
> {
> @@ -2899,10 +2862,23 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
> uint32_t count,
> case 0x80000002:
> case 0x80000003:
> case 0x80000004:
> - *eax = env->cpuid_model[(index - 0x80000002) * 4 + 0];
> - *ebx = env->cpuid_model[(index - 0x80000002) * 4 + 1];
> - *ecx = env->cpuid_model[(index - 0x80000002) * 4 + 2];
> - *edx = env->cpuid_model[(index - 0x80000002) * 4 + 3];
> + {
> + int i;
> + int len = strlen(env->model_id);
> + uint32_t model[4] = { 0, 0, 0, 0 };
> +
> + for (i = 0; i < 16; i++) {
> + int p = (index - 0x80000002) * 16 + i;
> + if (p >= len) {
> + continue;
> + }
> + model[i >> 2] |= ((uint8_t)env->model_id[p]) << (8 * (i &
> 3));
> + }
> + *eax = model[0];
> + *ebx = model[1];
> + *ecx = model[2];
> + *edx = model[3];
> + }
> break;
> case 0x80000005:
> /* cache info (L1 cache) */
> @@ -3868,9 +3844,6 @@ static void x86_cpu_initfn(Object *obj)
> object_property_add_str(obj, "vendor",
> x86_cpuid_get_vendor,
> x86_cpuid_set_vendor, NULL);
> - object_property_add_str(obj, "model-id",
> - x86_cpuid_get_model_id,
> - x86_cpuid_set_model_id, NULL);
> object_property_add(obj, "tsc-frequency", "int",
> x86_cpuid_get_tsc_freq,
> x86_cpuid_set_tsc_freq, NULL, NULL, NULL);
> @@ -4004,6 +3977,7 @@ static Property x86_cpu_properties[] = {
> DEFINE_PROP_UINT32("phys-bits", X86CPU, phys_bits, 0),
> DEFINE_PROP_BOOL("host-phys-bits", X86CPU, host_phys_bits, false),
> DEFINE_PROP_BOOL("fill-mtrr-mask", X86CPU, fill_mtrr_mask, true),
> + DEFINE_PROP_STRING("model-id", X86CPU, env.model_id),
> DEFINE_PROP_UINT32("level", X86CPU, env.cpuid_level, UINT32_MAX),
> DEFINE_PROP_UINT32("xlevel", X86CPU, env.cpuid_xlevel, UINT32_MAX),
> DEFINE_PROP_UINT32("xlevel2", X86CPU, env.cpuid_xlevel2, UINT32_MAX),
[Qemu-devel] [PATCH 2/4] target/i386: Use host_vendor_fms() in max_x86_cpu_initfn(), Eduardo Habkost, 2017/07/12
[Qemu-devel] [PATCH 3/4] target/i386: Define CPUID_MODEL_ID_SZ macro, Eduardo Habkost, 2017/07/12
[Qemu-devel] [PATCH 4/4] target/i386: Don't use x86_cpu_load_def() on "max" CPU model, Eduardo Habkost, 2017/07/12