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From: Igor Mammedov <imammedo@redhat.com>
To: Eduardo Habkost <ehabkost@redhat.com>
Cc: aliguori@us.ibm.com, stefanha@linux.vnet.ibm.com,
	gleb@redhat.com, jan.kiszka@siemens.com, mtosatti@redhat.com,
	mdroth@linux.vnet.ibm.com, qemu-devel@nongnu.org,
	blauwirbel@gmail.com, avi@redhat.com, pbonzini@redhat.com,
	akong@redhat.com, lersek@redhat.com, afaerber@suse.de
Subject: Re: [Qemu-devel] [RFC 11/20] target-i386: convert 'check' and 'enforce' features into properties
Date: Tue, 14 Aug 2012 23:18:47 +0200	[thread overview]
Message-ID: <20120814231847.1a9e4be2@thinkpad.mammed.net> (raw)
In-Reply-To: <20120810150904.GG4425@otherpad.lan.raisama.net>

On Fri, 10 Aug 2012 12:09:04 -0300
Eduardo Habkost <ehabkost@redhat.com> wrote:

> On Fri, Aug 10, 2012 at 01:22:27PM +0200, Igor Mammedov wrote:
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > ---
> >  target-i386/cpu.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++---------
> >  1 file changed, 57 insertions(+), 11 deletions(-)
> > 
> > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > index 7734613..a154e89 100644
> > --- a/target-i386/cpu.c
> > +++ b/target-i386/cpu.c
> > @@ -106,8 +106,8 @@ typedef struct model_features_t {
> >      uint32_t cpuid;
> >      } model_features_t;
> >  
> > -int check_cpuid = 0;
> > -int enforce_cpuid = 0;
> > +bool check_cpuid;
> > +bool enforce_cpuid;
> >  
> >  void host_cpuid(uint32_t function, uint32_t count,
> >                  uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
> > @@ -579,19 +579,20 @@ static int unavailable_host_feature(struct model_features_t *f, uint32_t mask)
> >   * their way to the guest.  Note: ft[].check_feat ideally should be
> >   * specified via a guest_def field to suppress report of extraneous flags.
> >   */
> > -static int check_features_against_host(x86_def_t *guest_def)
> > +static int check_features_against_host(X86CPU *cpu)
> >  {
> > +    CPUX86State *env = &cpu->env;
> >      x86_def_t host_def;
> >      uint32_t mask;
> >      int rv, i;
> >      struct model_features_t ft[] = {
> > -        {&guest_def->features, &host_def.features,
> > +        {&env->cpuid_features, &host_def.features,
> >              ~0, feature_name, 0x00000000},
> > -        {&guest_def->ext_features, &host_def.ext_features,
> > +        {&env->cpuid_ext_features, &host_def.ext_features,
> >              ~CPUID_EXT_HYPERVISOR, ext_feature_name, 0x00000001},
> > -        {&guest_def->ext2_features, &host_def.ext2_features,
> > +        {&env->cpuid_ext2_features, &host_def.ext2_features,
> >              ~PPRO_FEATURES, ext2_feature_name, 0x80000000},
> > -        {&guest_def->ext3_features, &host_def.ext3_features,
> > +        {&env->cpuid_ext3_features, &host_def.ext3_features,
> >              ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001}};
> >  
> >      cpu_x86_fill_host(&host_def);
> > @@ -1030,6 +1031,43 @@ static void x86_set_hv_vapic(Object *obj, Visitor *v, void *opaque,
> >  }
> >  #endif
> >  
> > +static void x86_cpuid_get_check(Object *obj, Visitor *v, void *opaque,
> > +                                         const char *name, Error **errp)
> > +{
> > +    visit_type_bool(v, &check_cpuid, name, errp);
> > +}
> > +
> > +static void x86_cpuid_set_check(Object *obj, Visitor *v, void *opaque,
> > +                                         const char *name, Error **errp)
> > +{
> > +    bool value;
> > +
> > +    visit_type_bool(v, &value, name, errp);
> > +    if (error_is_set(errp)) {
> > +        return;
> > +    }
> > +    check_cpuid = value;
> > +}
> > +
> > +static void x86_cpuid_get_enforce(Object *obj, Visitor *v, void *opaque,
> > +                                         const char *name, Error **errp)
> > +{
> > +    visit_type_bool(v, &enforce_cpuid, name, errp);
> > +}
> > +
> > +static void x86_cpuid_set_enforce(Object *obj, Visitor *v, void *opaque,
> > +                                         const char *name, Error **errp)
> > +{
> > +    bool value;
> > +
> > +    visit_type_bool(v, &value, name, errp);
> > +    if (error_is_set(errp)) {
> > +        return;
> > +    }
> > +    enforce_cpuid = value;
> > +    object_property_set_bool(obj, value, "check", errp);
> > +}
> > +
> >  static void cpudef_2_x86_cpu(X86CPU *cpu, x86_def_t *def, Error **errp)
> >  {
> >      CPUX86State *env = &cpu->env;
> > @@ -1225,10 +1263,6 @@ static int cpu_x86_find_by_name(X86CPU *cpu, x86_def_t *x86_cpu_def,
> >      x86_cpu_def->ext3_features &= ~minus_ext3_features;
> >      x86_cpu_def->kvm_features &= ~minus_kvm_features;
> >      x86_cpu_def->svm_features &= ~minus_svm_features;
> > -    if (check_cpuid) {
> > -        if (check_features_against_host(x86_cpu_def) && enforce_cpuid)
> > -            goto error;
> > -    }
> >      g_free(s);
> >      return 0;
> >  
> > @@ -1923,6 +1957,12 @@ void x86_cpu_realize(Object *obj, Error **errp)
> >          env->cpuid_svm_features &= TCG_SVM_FEATURES;
> >      }
> >  
> > +    if (check_cpuid && check_features_against_host(cpu)
> > +        && enforce_cpuid) {
> > +        error_set(errp, QERR_PERMISSION_DENIED);
> > +        return;
> > +    }
> > +
> 
> I just noticed that you changed behavior on patch 04/20 and now restore
> the behavior in this patch:
> 
> - Before patch 04/20, the feature check was being done after the
>   features were filtered according to the TCG support (meaning a feature
>   not supported by TCG will not trigger enforce/check errors).
before 04/20 check is done before TCG features filtering in
cpu_x86_find_by_name() and then later in cpu_x86_register() features are
TCG filtered.

> - After patch 04/20, the check was being done _before_ the features were
>   filtered according to TCG support (meaning a feature not supported by
>   TCG would trigger enforce/check errors).
> - With this patch, the old behavior is restored.
after 04/20, it is the same as before, i.e realize is called after
cpu_x86_register().

it's by mistake that in this patch I've put check after TCG filtering, I'll
fix it and do check before it.
> 
> I'm not sure which behavior is better. But we surely shouldn't silently
> move back and forth between those two modes.
> 
> IMO, checking _before_ the TCG filtering is better, as it's more
> predictable. it means having lots of warnings in case too-new CPU models
> are chosen in TCG model, but that's exactly the point.
> 
> 
> >  #ifndef CONFIG_USER_ONLY
> >      qemu_register_reset(x86_cpu_machine_reset_cb, cpu);
> >  #endif
> > @@ -1964,6 +2004,12 @@ static void x86_cpu_initfn(Object *obj)
> >      object_property_add(obj, "tsc-frequency", "int",
> >                          x86_cpuid_get_tsc_freq,
> >                          x86_cpuid_set_tsc_freq, NULL, NULL, NULL);
> > +    object_property_add(obj, "check", "bool",
> > +                        x86_cpuid_get_check,
> > +                        x86_cpuid_set_check, NULL, NULL, NULL);
> > +    object_property_add(obj, "enforce", "bool",
> > +                        x86_cpuid_get_enforce,
> > +                        x86_cpuid_set_enforce, NULL, NULL, NULL);
> >  #if !defined(CONFIG_USER_ONLY)
> >      object_property_add(obj, "hv_spinlocks", "int",
> >                          x86_get_hv_spinlocks,
> > -- 
> > 1.7.11.2
> > 
> 
> -- 
> Eduardo


-- 
Regards,
  Igor

  reply	other threads:[~2012-08-14 21:19 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-10 11:22 [Qemu-devel] [RFC 00/20] target-i386: convert CPU features into properties Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 01/20] target-i386: return Error from cpu_x86_find_by_name() Igor Mammedov
2012-08-11 12:19   ` Blue Swirl
2012-08-10 11:22 ` [Qemu-devel] [RFC 02/20] target-i386: cpu_x86_register(): report error from property setter Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 03/20] target-i386: if x86_cpu_realize() failed report error and do cleanup Igor Mammedov
2012-08-10 11:41   ` Andreas Färber
2012-08-10 11:22 ` [Qemu-devel] [RFC 04/20] target-i386: filter out not TCG features if running without kvm at realize time Igor Mammedov
2012-08-10 13:48   ` Eduardo Habkost
2012-08-10 11:22 ` [Qemu-devel] [RFC 05/20] target-i386: move out CPU features initialization in separate func Igor Mammedov
2012-08-10 13:53   ` Eduardo Habkost
2012-08-10 11:22 ` [Qemu-devel] [RFC 06/20] target-i386: xlevel should be more than 0x80000000, move fixup into setter Igor Mammedov
2012-08-10 14:44   ` Eduardo Habkost
2012-08-10 11:22 ` [Qemu-devel] [RFC 07/20] target-i386: convert cpuid features into properties Igor Mammedov
2012-08-10 14:50   ` Eduardo Habkost
2012-10-02 20:31   ` Eduardo Habkost
2012-08-10 11:22 ` [Qemu-devel] [RFC 08/20] target-i386: convert 'hv_spinlocks' feature into property Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 09/20] target-i386: convert 'hv_relaxed' " Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 10/20] target-i386: convert 'hv_vapic' " Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 11/20] target-i386: convert 'check' and 'enforce' features into properties Igor Mammedov
2012-08-10 15:09   ` Eduardo Habkost
2012-08-14 21:18     ` Igor Mammedov [this message]
2012-08-15 11:39       ` Eduardo Habkost
2012-08-15 12:11         ` Igor Mammedov
2012-08-15 12:19           ` Eduardo Habkost
2012-08-10 11:22 ` [Qemu-devel] [RFC 12/20] add visitor for parsing hz[KMG] input string Igor Mammedov
2012-08-10 11:57   ` Andreas Färber
2012-08-10 12:03     ` Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 13/20] target-i386: use visit_type_hz to parse tsc_freq property value Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 14/20] target-i386: introduce vendor-override property Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 15/20] target-i386: use define for cpuid vendor string size Igor Mammedov
2012-08-15 15:52   ` Pandarathil, Vijaymohan R
2012-08-15 16:06     ` Eduardo Habkost
2012-08-10 11:22 ` [Qemu-devel] [RFC 16/20] target-i386: replace uint32_t vendor fields by vendor string in x86_def_t Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 17/20] target-i386: parse cpu_model string into set of stringified properties Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 18/20] target-i386: use properties to set/unset user specified features on CPU Igor Mammedov
2012-08-13 20:48   ` Eduardo Habkost
2012-08-14 22:55     ` Igor Mammedov
2012-08-15 12:37   ` Eduardo Habkost
2012-08-15 12:41     ` Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 19/20] target-i386: move init of "hypervisor" feature into CPU initializer from cpudef Igor Mammedov
2012-08-10 11:22 ` [Qemu-devel] [RFC 20/20] target-i386: move default init of cpuid_kvm_features bitmap " Igor Mammedov
2012-08-10 15:24   ` Eduardo Habkost
2012-08-15 12:23     ` Igor Mammedov
2012-08-15 12:32       ` Eduardo Habkost
2012-08-10 11:39 ` [Qemu-devel] [RFC 00/20] target-i386: convert CPU features into properties Igor Mammedov

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