RE: [Xen-devel] VMX check in /xen/arch/x86/domain.c is invalid onx86-64 (at least AMD)

["Jonathan S. Shapiro" <shap@xxxxxxxxxxx>]

On Wed, 2005-05-11 at 22:28 -0700, Nakajima, Jun wrote:
> Jerone Young wrote:
> > if (!(c->flags & ECF_VMX_GUEST))
> >         if ( ((c->cpu_ctxt.cs & 3) == 0) ||
> >              ((c->cpu_ctxt.ss & 3) == 0) )
> >                 return -EINVAL;
> > 
> > This check in /xen/arch/x86/domain.c (line 394) is invalid for AMD
> > x86-64 as this field 1<<1 is a reserved field in the rflags (name for
> > 64bit eflags) that reads as 1. This can be found in the AMD x86-64
> > Programming manual vol 2 on page 65. Below is the code, I'm not sure
> > how to put an ifdef around since I'm not sure if Intel's EMT64 with
> > VMX cpus have the same rflag reserved (which if this check is correct
> > they do)? This helps break x86-64 building domU domains.
> 
> This c->flags has nothing to do with the machine architecture, but it's
> just a software field for the domain builder to specify the type of the
> domain (i.e. VMX or not, for example). The rflags is in
> execution_context_t.

Then it *definitely* should not be named flags. Perhaps rename to
domFlags?


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