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Re: [libvirt] [Qemu-devel] [PATCH qom-cpu 05/11] target-i386: check/enforce: Fix CPUID leaf numbers on error messages



On Sun, Jan 06, 2013 at 04:12:54PM +0200, Gleb Natapov wrote:
> On Fri, Jan 04, 2013 at 08:01:06PM -0200, Eduardo Habkost wrote:
> > The -cpu check/enforce warnings are printing incorrect information about the
> > missing flags. There are no feature flags on CPUID leaves 0 and 0x80000000, but
> > there were references to 0 and 0x80000000 in the table at
> > kvm_check_features_against_host().
> > 
> > This changes the model_features_t struct to contain the register number as
> > well, so the error messages print the correct CPUID leaf+register information,
> > instead of wrong CPUID leaf numbers.
> > 
> > This also changes the format of the error messages, so they follow the
> > "CPUID.<leaf>.<register>.<name> [bit <offset>]" convention used on Intel
> > documentation. Example output:
> > 
> >     $ qemu-system-x86_64 -machine pc-1.0,accel=kvm -cpu Opteron_G4,+ia64,enforce
> >     warning: host doesn't support requested feature: CPUID.01H:EDX.ia64 [bit 30]
> >     warning: host doesn't support requested feature: CPUID.01H:ECX.xsave [bit 26]
> >     warning: host doesn't support requested feature: CPUID.01H:ECX.avx [bit 28]
> >     warning: host doesn't support requested feature: CPUID.80000001H:ECX.abm [bit 5]
> >     warning: host doesn't support requested feature: CPUID.80000001H:ECX.sse4a [bit 6]
> >     warning: host doesn't support requested feature: CPUID.80000001H:ECX.misalignsse [bit 7]
> >     warning: host doesn't support requested feature: CPUID.80000001H:ECX.3dnowprefetch [bit 8]
> >     warning: host doesn't support requested feature: CPUID.80000001H:ECX.xop [bit 11]
> >     warning: host doesn't support requested feature: CPUID.80000001H:ECX.fma4 [bit 16]
> >     Unable to find x86 CPU definition
> >     $
> > 
> > Signed-off-by: Eduardo Habkost <ehabkost redhat com>
> Reviewed-by: Gleb Natapov <gleb redhat com>
> But see the question below.
Never mind. I found the answer in the following patches :)

> 
> > ---
> > Cc: Gleb Natapov <gleb redhat com>
> > Cc: Marcelo Tosatti <mtosatti redhat com>
> > Cc: kvm vger kernel org
> > 
> > Changes v2:
> >  - Coding style fixes
> >  - Add assert() for invalid register numbers on
> >    unavailable_host_feature()
> > ---
> >  target-i386/cpu.c | 42 +++++++++++++++++++++++++++++++++---------
> >  target-i386/cpu.h |  3 +++
> >  2 files changed, 36 insertions(+), 9 deletions(-)
> > 
> > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > index e916ae0..c3e5db8 100644
> > --- a/target-i386/cpu.c
> > +++ b/target-i386/cpu.c
> > @@ -124,6 +124,25 @@ static const char *cpuid_7_0_ebx_feature_name[] = {
> >      NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
> >  };
> >  
> > +const char *get_register_name_32(unsigned int reg)
> > +{
> > +    static const char *reg_names[CPU_NB_REGS32] = {
> > +        [R_EAX] = "EAX",
> > +        [R_ECX] = "ECX",
> > +        [R_EDX] = "EDX",
> > +        [R_EBX] = "EBX",
> > +        [R_ESP] = "ESP",
> > +        [R_EBP] = "EBP",
> > +        [R_ESI] = "ESI",
> > +        [R_EDI] = "EDI",
> > +    };
> > +
> > +    if (reg > CPU_NB_REGS32) {
> > +        return NULL;
> > +    }
> > +    return reg_names[reg];
> > +}
> > +
> >  /* collects per-function cpuid data
> >   */
> >  typedef struct model_features_t {
> > @@ -132,7 +151,8 @@ typedef struct model_features_t {
> >      uint32_t check_feat;
> >      const char **flag_names;
> >      uint32_t cpuid;
> > -    } model_features_t;
> > +    int reg;
> > +} model_features_t;
> >  
> >  int check_cpuid = 0;
> >  int enforce_cpuid = 0;
> > @@ -923,10 +943,13 @@ static int unavailable_host_feature(struct model_features_t *f, uint32_t mask)
> >  
> >      for (i = 0; i < 32; ++i)
> >          if (1 << i & mask) {
> > -            fprintf(stderr, "warning: host cpuid %04x_%04x lacks requested"
> > -                " flag '%s' [0x%08x]\n",
> > -                f->cpuid >> 16, f->cpuid & 0xffff,
> > -                f->flag_names[i] ? f->flag_names[i] : "[reserved]", mask);
> > +            const char *reg = get_register_name_32(f->reg);
> > +            assert(reg);
> > +            fprintf(stderr, "warning: host doesn't support requested feature: "
> > +                "CPUID.%02XH:%s%s%s [bit %d]\n",
> > +                f->cpuid, reg,
> > +                f->flag_names[i] ? "." : "",
> > +                f->flag_names[i] ? f->flag_names[i] : "", i);
> >              break;
> >          }
> >      return 0;
> > @@ -945,13 +968,14 @@ static int kvm_check_features_against_host(x86_def_t *guest_def)
> >      int rv, i;
> >      struct model_features_t ft[] = {
> >          {&guest_def->features, &host_def.features,
> > -            ~0, feature_name, 0x00000000},
> > +            ~0, feature_name, 0x00000001, R_EDX},
> >          {&guest_def->ext_features, &host_def.ext_features,
> > -            ~CPUID_EXT_HYPERVISOR, ext_feature_name, 0x00000001},
> > +            ~CPUID_EXT_HYPERVISOR, ext_feature_name, 0x00000001, R_ECX},
> >          {&guest_def->ext2_features, &host_def.ext2_features,
> > -            ~PPRO_FEATURES, ext2_feature_name, 0x80000000},
> > +            ~PPRO_FEATURES, ext2_feature_name, 0x80000001, R_EDX},
> >          {&guest_def->ext3_features, &host_def.ext3_features,
> > -            ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001}};
> > +            ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001, R_ECX}
> Why do we exclude PPRO_FEATURES/CPUID_EXT3_SVM from been checked?
> 
> > +    };
> >  
> >      assert(kvm_enabled());
> >  
> > diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> > index 27c8d0c..ab81a5c 100644
> > --- a/target-i386/cpu.h
> > +++ b/target-i386/cpu.h
> > @@ -1221,4 +1221,7 @@ void cpu_report_tpr_access(CPUX86State *env, TPRAccess access);
> >  void enable_kvm_pv_eoi(void);
> >  void disable_kvm_mmu_op(void);
> >  
> > +/* Return name of 32-bit register, from a R_* constant */
> > +const char *get_register_name_32(unsigned int reg);
> > +
> >  #endif /* CPU_I386_H */
> > -- 
> > 1.7.11.7
> 
> --
> 			Gleb.

--
			Gleb.


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