[Xen-devel] In VMCS, HOST_CR0.TS is always set 1. Why?

["Cui, Dexuan" <dexuan.cui@xxxxxxxxx>]

> changeset 15216: 6f13c3be08fa
http://xenbits.xensource.com/xen-unstable.hg?rev/6f13c3be08fa
> --- a/xen/arch/x86/hvm/vmx/vmcs.c     Mon Jun 04 15:41:32 2007 +0100
> +++ b/xen/arch/x86/hvm/vmx/vmcs.c     Mon Jun 04 16:47:48 2007 +0100
> @@ -337,7 +337,7 @@ static void construct_vmcs(struct vcpu *
>  #endif
 
>      /* Host control registers. */
> -    __vmwrite(HOST_CR0, read_cr0());
> +    __vmwrite(HOST_CR0, read_cr0() | X86_CR0_TS);
>      __vmwrite(HOST_CR4, read_cr4());
>  
>      /* Host CS:RIP. */

Hi Steven,
The description of the changeset says "This fixes a number of subtle FP
corruption issues within PV domains when running alongside VMX ones" --
can you tell me what the subtle issues are?

Thanks!

-- Dexuan

 

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