[Qemu-devel] [PATCH] enable SVM EFER bit

[Qemu-devel] [PATCH] enable SVM EFER bit

[Alexander Graf]

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Due to the recently introduces checks for SVM activation, the SVM 
instructions currently throw a #UD exception if they are not activated. 
The activation happens through a write to the EFER which does not 
support the SVM bit yet.

This patch adds the SVME bit to the EFER MSR write. It makes KVM work 
for me again.

Alex




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Index: target-i386/op_helper.c
===================================================================
--- target-i386/op_helper.c	(revision 4652)
+++ target-i386/op_helper.c	(working copy)
@@ -3069,6 +3069,8 @@
                 update_mask |= MSR_EFER_FFXSR;
             if (env->cpuid_ext2_features & CPUID_EXT2_NX)
                 update_mask |= MSR_EFER_NXE;
+            if (env->cpuid_ext3_features & CPUID_EXT3_SVM)
+                update_mask |= MSR_EFER_SVME;
             env->efer = (env->efer & ~update_mask) |
             (val & update_mask);
         }

Re: [Qemu-devel] [PATCH] enable SVM EFER bit

[Anthony Liguori]

Alexander Graf wrote:
> Due to the recently introduces checks for SVM activation, the SVM 
> instructions currently throw a #UD exception if they are not 
> activated. The activation happens through a write to the EFER which 
> does not support the SVM bit yet.
>
> This patch adds the SVME bit to the EFER MSR write. It makes KVM work 
> for me again.

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>

Regards,

Anthony Liguori

> Alex
>
>
>

[Qemu-devel] Re: [PATCH] enable SVM EFER bit

[Fabrice Bellard]

Alexander Graf wrote:
> Due to the recently introduces checks for SVM activation, the SVM 
> instructions currently throw a #UD exception if they are not activated. 
> The activation happens through a write to the EFER which does not 
> support the SVM bit yet.
> 
> This patch adds the SVME bit to the EFER MSR write. It makes KVM work 
> for me again.

OK for the problem, but the fix is not OK because you don't synchronize 
the hflags. It is strange that SVM can even work with that... I am 
working on a better fix.

Fabrice.

[Qemu-devel] Re: [PATCH] enable SVM EFER bit

[Alexander Graf]

On Jun 4, 2008, at 3:02 PM, Fabrice Bellard wrote:

> Alexander Graf wrote:
>> Due to the recently introduces checks for SVM activation, the SVM  
>> instructions currently throw a #UD exception if they are not  
>> activated. The activation happens through a write to the EFER which  
>> does not support the SVM bit yet.
>> This patch adds the SVME bit to the EFER MSR write. It makes KVM  
>> work for me again.
>
> OK for the problem, but the fix is not OK because you don't  
> synchronize the hflags. It is strange that SVM can even work with  
> that... I am working on a better fix.

a write to MSR_EFER calls cpu_load_efer() which updates the hflags.

Alex

[Qemu-devel] Re: [PATCH] enable SVM EFER bit

[Alexander Graf]

On Jun 4, 2008, at 3:02 PM, Fabrice Bellard wrote:

> Alexander Graf wrote:
>> Due to the recently introduces checks for SVM activation, the SVM  
>> instructions currently throw a #UD exception if they are not  
>> activated. The activation happens through a write to the EFER which  
>> does not support the SVM bit yet.
>> This patch adds the SVME bit to the EFER MSR write. It makes KVM  
>> work for me again.
>
> OK for the problem, but the fix is not OK because you don't  
> synchronize the hflags. It is strange that SVM can even work with  
> that... I am working on a better fix.

Wow I should probably not look at your fixed code when replying :-).  
You're just too fast for me.

Alex