Patchwork [27/28] target-i386: kvm_cpu_fill_host: use GET_SUPPORTED_CPUID

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Submitter Marcelo Tosatti
Date Oct. 31, 2012, 9:40 a.m.
Message ID <12869995ea4f436ab76af5059fd2e9ae83c6cf9d.1351676406.git.mtosatti@redhat.com>
Download mbox | patch
Permalink /patch/195831/
State New
Headers show

Comments

Marcelo Tosatti - Oct. 31, 2012, 9:40 a.m.
From: Eduardo Habkost <ehabkost@redhat.com>

Change the kvm_cpu_fill_host() function to use
kvm_arch_get_supported_cpuid() instead of running the CPUID instruction
directly, when checking for supported CPUID features.

This should solve two problems at the same time:

 * "-cpu host" was not enabling features that don't need support on
   the host CPU (e.g. x2apic);
 * "check" and "enforce" options were not detecting problems when the
   host CPU did support a feature, but the KVM kernel code didn't
   support it.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
 target-i386/cpu.c |   25 +++++++++++++++----------
 1 files changed, 15 insertions(+), 10 deletions(-)
Andreas Färber - Nov. 2, 2012, 3:34 p.m.
Am 31.10.2012 10:40, schrieb Marcelo Tosatti:
> From: Eduardo Habkost <ehabkost@redhat.com>
> 
> Change the kvm_cpu_fill_host() function to use
> kvm_arch_get_supported_cpuid() instead of running the CPUID instruction
> directly, when checking for supported CPUID features.
> 
> This should solve two problems at the same time:
> 
>  * "-cpu host" was not enabling features that don't need support on
>    the host CPU (e.g. x2apic);
>  * "check" and "enforce" options were not detecting problems when the
>    host CPU did support a feature, but the KVM kernel code didn't
>    support it.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> ---
>  target-i386/cpu.c |   25 +++++++++++++++----------
>  1 files changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 390ed47..4c84e9f 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -773,13 +773,13 @@ static int cpu_x86_fill_model_id(char *str)
>   */
>  static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
>  {
> +    KVMState *s = kvm_state;

This broke the linux-user build:

target-i386/cpu.o: In function `kvm_cpu_fill_host':
/home/andreas/QEMU/qemu-rcar/target-i386/cpu.c:783: undefined reference
to `kvm_state'
collect2: error: ld returned 1 exit status
make[1]: *** [qemu-i386] Fehler 1
make: *** [subdir-i386-linux-user] Fehler 2

Any idea how to fix?

Andreas

>      uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
>  
>      assert(kvm_enabled());
>  
>      x86_cpu_def->name = "host";
>      host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
> -    x86_cpu_def->level = eax;
>      x86_cpu_def->vendor1 = ebx;
>      x86_cpu_def->vendor2 = edx;
>      x86_cpu_def->vendor3 = ecx;
> @@ -788,21 +788,24 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
>      x86_cpu_def->family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
>      x86_cpu_def->model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
>      x86_cpu_def->stepping = eax & 0x0F;
> -    x86_cpu_def->ext_features = ecx;
> -    x86_cpu_def->features = edx;
> +
> +    x86_cpu_def->level = kvm_arch_get_supported_cpuid(s, 0x0, 0, R_EAX);
> +    x86_cpu_def->features = kvm_arch_get_supported_cpuid(s, 0x1, 0, R_EDX);
> +    x86_cpu_def->ext_features = kvm_arch_get_supported_cpuid(s, 0x1, 0, R_ECX);
>  
>      if (x86_cpu_def->level >= 7) {
> -        x86_cpu_def->cpuid_7_0_ebx_features = kvm_arch_get_supported_cpuid(kvm_state, 0x7, 0, R_EBX);
> +        x86_cpu_def->cpuid_7_0_ebx_features =
> +                    kvm_arch_get_supported_cpuid(s, 0x7, 0, R_EBX);
>      } else {
>          x86_cpu_def->cpuid_7_0_ebx_features = 0;
>      }
>  
> -    host_cpuid(0x80000000, 0, &eax, &ebx, &ecx, &edx);
> -    x86_cpu_def->xlevel = eax;
> +    x86_cpu_def->xlevel = kvm_arch_get_supported_cpuid(s, 0x80000000, 0, R_EAX);
> +    x86_cpu_def->ext2_features =
> +                kvm_arch_get_supported_cpuid(s, 0x80000001, 0, R_EDX);
> +    x86_cpu_def->ext3_features =
> +                kvm_arch_get_supported_cpuid(s, 0x80000001, 0, R_ECX);
>  
> -    host_cpuid(0x80000001, 0, &eax, &ebx, &ecx, &edx);
> -    x86_cpu_def->ext2_features = edx;
> -    x86_cpu_def->ext3_features = ecx;
>      cpu_x86_fill_model_id(x86_cpu_def->model_id);
>      x86_cpu_def->vendor_override = 0;
>  
> @@ -811,11 +814,13 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
>          x86_cpu_def->vendor2 == CPUID_VENDOR_VIA_2 &&
>          x86_cpu_def->vendor3 == CPUID_VENDOR_VIA_3) {
>          host_cpuid(0xC0000000, 0, &eax, &ebx, &ecx, &edx);
> +        eax = kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX);
>          if (eax >= 0xC0000001) {
>              /* Support VIA max extended level */
>              x86_cpu_def->xlevel2 = eax;
>              host_cpuid(0xC0000001, 0, &eax, &ebx, &ecx, &edx);
> -            x86_cpu_def->ext4_features = edx;
> +            x86_cpu_def->ext4_features =
> +                    kvm_arch_get_supported_cpuid(s, 0xC0000001, 0, R_EDX);
>          }
>      }
>  
>
Eduardo Habkost - Nov. 2, 2012, 4:05 p.m.
On Fri, Nov 02, 2012 at 04:34:00PM +0100, Andreas Färber wrote:
> Am 31.10.2012 10:40, schrieb Marcelo Tosatti:
> > From: Eduardo Habkost <ehabkost@redhat.com>
> > 
> > Change the kvm_cpu_fill_host() function to use
> > kvm_arch_get_supported_cpuid() instead of running the CPUID instruction
> > directly, when checking for supported CPUID features.
> > 
> > This should solve two problems at the same time:
> > 
> >  * "-cpu host" was not enabling features that don't need support on
> >    the host CPU (e.g. x2apic);
> >  * "check" and "enforce" options were not detecting problems when the
> >    host CPU did support a feature, but the KVM kernel code didn't
> >    support it.
> > 
> > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> > ---
> >  target-i386/cpu.c |   25 +++++++++++++++----------
> >  1 files changed, 15 insertions(+), 10 deletions(-)
> > 
> > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > index 390ed47..4c84e9f 100644
> > --- a/target-i386/cpu.c
> > +++ b/target-i386/cpu.c
> > @@ -773,13 +773,13 @@ static int cpu_x86_fill_model_id(char *str)
> >   */
> >  static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
> >  {
> > +    KVMState *s = kvm_state;
> 
> This broke the linux-user build:
> 
> target-i386/cpu.o: In function `kvm_cpu_fill_host':
> /home/andreas/QEMU/qemu-rcar/target-i386/cpu.c:783: undefined reference
> to `kvm_state'
> collect2: error: ld returned 1 exit status
> make[1]: *** [qemu-i386] Fehler 1
> make: *** [subdir-i386-linux-user] Fehler 2
> 
> Any idea how to fix?

This function should never be called without CONFIG_KVM, so we can
#ifdef out the whole function body. I will send a patch shortly.


> 
> Andreas
> 
> >      uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
> >  
> >      assert(kvm_enabled());
> >  
> >      x86_cpu_def->name = "host";
> >      host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
> > -    x86_cpu_def->level = eax;
> >      x86_cpu_def->vendor1 = ebx;
> >      x86_cpu_def->vendor2 = edx;
> >      x86_cpu_def->vendor3 = ecx;
> > @@ -788,21 +788,24 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
> >      x86_cpu_def->family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
> >      x86_cpu_def->model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
> >      x86_cpu_def->stepping = eax & 0x0F;
> > -    x86_cpu_def->ext_features = ecx;
> > -    x86_cpu_def->features = edx;
> > +
> > +    x86_cpu_def->level = kvm_arch_get_supported_cpuid(s, 0x0, 0, R_EAX);
> > +    x86_cpu_def->features = kvm_arch_get_supported_cpuid(s, 0x1, 0, R_EDX);
> > +    x86_cpu_def->ext_features = kvm_arch_get_supported_cpuid(s, 0x1, 0, R_ECX);
> >  
> >      if (x86_cpu_def->level >= 7) {
> > -        x86_cpu_def->cpuid_7_0_ebx_features = kvm_arch_get_supported_cpuid(kvm_state, 0x7, 0, R_EBX);
> > +        x86_cpu_def->cpuid_7_0_ebx_features =
> > +                    kvm_arch_get_supported_cpuid(s, 0x7, 0, R_EBX);
> >      } else {
> >          x86_cpu_def->cpuid_7_0_ebx_features = 0;
> >      }
> >  
> > -    host_cpuid(0x80000000, 0, &eax, &ebx, &ecx, &edx);
> > -    x86_cpu_def->xlevel = eax;
> > +    x86_cpu_def->xlevel = kvm_arch_get_supported_cpuid(s, 0x80000000, 0, R_EAX);
> > +    x86_cpu_def->ext2_features =
> > +                kvm_arch_get_supported_cpuid(s, 0x80000001, 0, R_EDX);
> > +    x86_cpu_def->ext3_features =
> > +                kvm_arch_get_supported_cpuid(s, 0x80000001, 0, R_ECX);
> >  
> > -    host_cpuid(0x80000001, 0, &eax, &ebx, &ecx, &edx);
> > -    x86_cpu_def->ext2_features = edx;
> > -    x86_cpu_def->ext3_features = ecx;
> >      cpu_x86_fill_model_id(x86_cpu_def->model_id);
> >      x86_cpu_def->vendor_override = 0;
> >  
> > @@ -811,11 +814,13 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
> >          x86_cpu_def->vendor2 == CPUID_VENDOR_VIA_2 &&
> >          x86_cpu_def->vendor3 == CPUID_VENDOR_VIA_3) {
> >          host_cpuid(0xC0000000, 0, &eax, &ebx, &ecx, &edx);
> > +        eax = kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX);
> >          if (eax >= 0xC0000001) {
> >              /* Support VIA max extended level */
> >              x86_cpu_def->xlevel2 = eax;
> >              host_cpuid(0xC0000001, 0, &eax, &ebx, &ecx, &edx);
> > -            x86_cpu_def->ext4_features = edx;
> > +            x86_cpu_def->ext4_features =
> > +                    kvm_arch_get_supported_cpuid(s, 0xC0000001, 0, R_EDX);
> >          }
> >      }
> >  
> > 
> 
> 
> -- 
> SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
> GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg

Patch

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 390ed47..4c84e9f 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -773,13 +773,13 @@  static int cpu_x86_fill_model_id(char *str)
  */
 static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
 {
+    KVMState *s = kvm_state;
     uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
 
     assert(kvm_enabled());
 
     x86_cpu_def->name = "host";
     host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
-    x86_cpu_def->level = eax;
     x86_cpu_def->vendor1 = ebx;
     x86_cpu_def->vendor2 = edx;
     x86_cpu_def->vendor3 = ecx;
@@ -788,21 +788,24 @@  static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
     x86_cpu_def->family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
     x86_cpu_def->model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
     x86_cpu_def->stepping = eax & 0x0F;
-    x86_cpu_def->ext_features = ecx;
-    x86_cpu_def->features = edx;
+
+    x86_cpu_def->level = kvm_arch_get_supported_cpuid(s, 0x0, 0, R_EAX);
+    x86_cpu_def->features = kvm_arch_get_supported_cpuid(s, 0x1, 0, R_EDX);
+    x86_cpu_def->ext_features = kvm_arch_get_supported_cpuid(s, 0x1, 0, R_ECX);
 
     if (x86_cpu_def->level >= 7) {
-        x86_cpu_def->cpuid_7_0_ebx_features = kvm_arch_get_supported_cpuid(kvm_state, 0x7, 0, R_EBX);
+        x86_cpu_def->cpuid_7_0_ebx_features =
+                    kvm_arch_get_supported_cpuid(s, 0x7, 0, R_EBX);
     } else {
         x86_cpu_def->cpuid_7_0_ebx_features = 0;
     }
 
-    host_cpuid(0x80000000, 0, &eax, &ebx, &ecx, &edx);
-    x86_cpu_def->xlevel = eax;
+    x86_cpu_def->xlevel = kvm_arch_get_supported_cpuid(s, 0x80000000, 0, R_EAX);
+    x86_cpu_def->ext2_features =
+                kvm_arch_get_supported_cpuid(s, 0x80000001, 0, R_EDX);
+    x86_cpu_def->ext3_features =
+                kvm_arch_get_supported_cpuid(s, 0x80000001, 0, R_ECX);
 
-    host_cpuid(0x80000001, 0, &eax, &ebx, &ecx, &edx);
-    x86_cpu_def->ext2_features = edx;
-    x86_cpu_def->ext3_features = ecx;
     cpu_x86_fill_model_id(x86_cpu_def->model_id);
     x86_cpu_def->vendor_override = 0;
 
@@ -811,11 +814,13 @@  static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
         x86_cpu_def->vendor2 == CPUID_VENDOR_VIA_2 &&
         x86_cpu_def->vendor3 == CPUID_VENDOR_VIA_3) {
         host_cpuid(0xC0000000, 0, &eax, &ebx, &ecx, &edx);
+        eax = kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX);
         if (eax >= 0xC0000001) {
             /* Support VIA max extended level */
             x86_cpu_def->xlevel2 = eax;
             host_cpuid(0xC0000001, 0, &eax, &ebx, &ecx, &edx);
-            x86_cpu_def->ext4_features = edx;
+            x86_cpu_def->ext4_features =
+                    kvm_arch_get_supported_cpuid(s, 0xC0000001, 0, R_EDX);
         }
     }