Re: [Qemu-devel] [PATCH v2] target-i386: use static properties to list CPUID features

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 23 Oct 2012 11:51:49 -0200
Eduardo Habkost <ehabkost@redhat.com> wrote:

> On Tue, Oct 23, 2012 at 03:26:40PM +0200, Igor Mammedov wrote:
> > convert x86_cpu_list() to use QDEV_FIND_PROP_FROM_BIT() for getting
> > CPUID feature name.
> > In addition since x86_cpu_list() was the last user of *feature_name
> > arrays, clean them up.
> > 
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > ---
> > v2:
> >   * fix x86_cpu_list(), use X86CPU as base to count offset correctly
> >   * Do not forget to print 0 bit
> > ---
> >  target-i386/cpu.c | 106 +++++++++++-------------------------------------------
> >  1 file changed, 20 insertions(+), 86 deletions(-)
> > 
> > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > index 5e6b77d..ff29cfa 100644
> > --- a/target-i386/cpu.c
> > +++ b/target-i386/cpu.c
> > @@ -38,55 +38,6 @@
> >  #include <linux/kvm_para.h>
> >  #endif
> >  
> > -/* feature flags taken from "Intel Processor Identification and the CPUID
> > - * Instruction" and AMD's "CPUID Specification".  In cases of disagreement
> > - * between feature naming conventions, aliases may be added.
> > - */
> > -static const char *feature_name[] = {
> > -    "fpu", "vme", "de", "pse",
> > -    "tsc", "msr", "pae", "mce",
> > -    "cx8", "apic", NULL, "sep",
> > -    "mtrr", "pge", "mca", "cmov",
> > -    "pat", "pse36", "pn" /* Intel psn */, "clflush" /* Intel clfsh */,
> > -    NULL, "ds" /* Intel dts */, "acpi", "mmx",
> > -    "fxsr", "sse", "sse2", "ss",
> > -    "ht" /* Intel htt */, "tm", "ia64", "pbe",
> > -};
> > -static const char *ext_feature_name[] = {
> > -    "pni|sse3" /* Intel,AMD sse3 */, "pclmulqdq|pclmuldq", "dtes64", "monitor",
> > -    "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",
> > -    "tsc-deadline", "aes", "xsave", "osxsave",
> > -    "avx", NULL, NULL, "hypervisor",
> > -};
> > -/* Feature names that are already defined on feature_name[] but are set on
> > - * CPUID[8000_0001].EDX on AMD CPUs don't have their names on
> > - * ext2_feature_name[]. They are copied automatically to cpuid_ext2_features
> > - * if and only if CPU vendor is AMD.
> > - */
> > -static const char *ext2_feature_name[] = {
> > -    NULL /* fpu */, NULL /* vme */, NULL /* de */, NULL /* pse */,
> > -    NULL /* tsc */, NULL /* msr */, NULL /* pae */, NULL /* mce */,
> > -    NULL /* cx8 */ /* AMD CMPXCHG8B */, NULL /* apic */, NULL, "syscall",
> > -    NULL /* mtrr */, NULL /* pge */, NULL /* mca */, NULL /* cmov */,
> > -    NULL /* pat */, NULL /* pse36 */, NULL, NULL /* Linux mp */,
> > -    "nx|xd", NULL, "mmxext", NULL /* mmx */,
> > -    NULL /* fxsr */, "fxsr_opt|ffxsr", "pdpe1gb" /* AMD Page1GB */, "rdtscp",
> > -};
> > -static const char *ext3_feature_name[] = {
> > -    "lahf_lm" /* AMD LahfSahf */, "cmp_legacy", "svm", "extapic" /* AMD ExtApicSpace */,
> > -    "cr8legacy" /* AMD AltMovCr8 */, "abm", "sse4a", "misalignsse",
> > -    "3dnowprefetch", "osvw", "ibs", "xop",
> > -    "skinit", "wdt", NULL, NULL,
> > -    "fma4", NULL, "cvt16", "nodeid_msr",
> > -    NULL, NULL, NULL, NULL,
> > -    NULL, NULL, NULL, NULL,
> > -    NULL, NULL, NULL, NULL,
> > -};
> > -
> >  #if defined(CONFIG_KVM)
> >  static void x86_cpu_get_kvmclock(Object *obj, Visitor *v, void *opaque,
> >                                   const char *name, Error **errp)
> > @@ -1495,35 +1446,22 @@ error:
> >      return -1;
> >  }
> >  
> > -/* generate a composite string into buf of all cpuid names in featureset
> > - * selected by fbits.  indicate truncation at bufsize in the event of overflow.
> > - * if flags, suppress names undefined in featureset.
> > - */
> > -static void listflags(char *buf, int bufsize, uint32_t fbits,
> > -    const char **featureset, uint32_t flags)
> > -{
> > -    const char **p = &featureset[31];
> > -    char *q, *b, bit;
> > -    int nc;
> > -
> > -    b = 4 <= bufsize ? buf + (bufsize -= 3) - 1 : NULL;
> > -    *buf = '\0';
> > -    for (q = buf, bit = 31; fbits && bufsize; --p, fbits &= ~(1 << bit), --bit)
> > -        if (fbits & 1 << bit && (*p || !flags)) {
> > -            if (*p)
> > -                nc = snprintf(q, bufsize, "%s%s", q == buf ? "" : " ", *p);
> > -            else
> > -                nc = snprintf(q, bufsize, "%s[%d]", q == buf ? "" : " ", bit);
> > -            if (bufsize <= nc) {
> > -                if (b) {
> > -                    memcpy(b, "...", sizeof("..."));
> > -                }
> > -                return;
> > -            }
> > -            q += nc;
> > -            bufsize -= nc;
> > -        }
> > -}
> > +#define LIST_FLAGS(_typename, _state, _field)                      \
> > +    do {                                                           \
> > +        int i;                                                     \
> > +        const Property *prop;                                      \
> > +        const DeviceClass *dc;                                     \
> > +        dc = DEVICE_CLASS(object_class_by_name((_typename)));      \
> > +        (*cpu_fprintf)(f, " ");                                    \
> > +        for (i = 31; i >= 0; --i) {                                \
> > +            prop = QDEV_FIND_PROP_FROM_BIT(dc, _state, _field, i); \
> > +            if (prop) {                                            \
> > +                /* for compatibility do not print f- prefix */     \
> > +                (*cpu_fprintf)(f, " %s", prop->name + 2);          \
> > +            }                                                      \
> > +        }                                                          \
> > +        (*cpu_fprintf)(f, "\n");                                   \
> > +    } while (0)
> >  
> >  /* generate CPU information. */
> >  void x86_cpu_list(FILE *f, fprintf_function cpu_fprintf)
> > @@ -1539,14 +1477,10 @@ void x86_cpu_list(FILE *f, fprintf_function cpu_fprintf)
> >          (*cpu_fprintf)(f, "x86 %16s\n", "[host]");
> >      }
> >      (*cpu_fprintf)(f, "\nRecognized CPUID flags:\n");
> > -    listflags(buf, sizeof(buf), (uint32_t)~0, feature_name, 1);
> > -    (*cpu_fprintf)(f, "  %s\n", buf);
> > -    listflags(buf, sizeof(buf), (uint32_t)~0, ext_feature_name, 1);
> > -    (*cpu_fprintf)(f, "  %s\n", buf);
> > -    listflags(buf, sizeof(buf), (uint32_t)~0, ext2_feature_name, 1);
> > -    (*cpu_fprintf)(f, "  %s\n", buf);
> > -    listflags(buf, sizeof(buf), (uint32_t)~0, ext3_feature_name, 1);
> > -    (*cpu_fprintf)(f, "  %s\n", buf);
> > +    LIST_FLAGS(TYPE_X86_CPU, X86CPU, env.cpuid_features);
> > +    LIST_FLAGS(TYPE_X86_CPU, X86CPU, env.cpuid_ext_features);
> > +    LIST_FLAGS(TYPE_X86_CPU, X86CPU, env.cpuid_ext2_features);
> > +    LIST_FLAGS(TYPE_X86_CPU, X86CPU, env.cpuid_ext3_features);
> 
> Do we really need to filter the property list and list only the ones
> that correspond to feature bits in the X86CPU struct?
> 
> I mean: the specific X86CPU struct field where the CPU property bit is
> being stored isn't part of the interface. For external code, all that
> matters are the property names/types, the struct fields/offsets are
> internal implementation details.
> 
> IMO we can simply list all recognized X86CPU properties, or (if listing
> all the properties is too much) list all the CPU properties that start
> with "f-".
Probably "f-" will be better because it won't surprise users who expect only
CPUID feature flags that was so far printed here.
I'll do it for the next respin.

> 
> -- 
> Eduardo
> 


-- 
Regards,
  Igor