Re: [Xen-devel] [PATCH v4 08/10] nEPT: handle invept instruction from L1 VMM

["Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx>]

> >
> > +int nvmx_handle_invept(struct cpu_user_regs *regs) {
> > +    struct vmx_inst_decoded decode;
> > +    unsigned long eptp;
> > +    u64 inv_type;
> > +
> > +    if ( decode_vmx_inst(regs, &decode, &eptp, 0) != X86EMUL_OKAY )
> > +        return X86EMUL_EXCEPTION;
> 
> So in the overview you said you fixed this, but here it is again:
> There are more than the two X86EMUL_* values referenced above, and
> hence you can't imply that if it's not one, it's the other.

Do you mean X86EMUL_EXCEPTION can't be returned here ?   I think 
decode_vmx_inst handles the exception  already, and the caller doesn't need to 
do anything.   Once the caller of nvmx_handle_invept get this return value,  it 
doesn't do RIP++, and just inject one exception instead in its return path.  

> > +
> > +    inv_type = reg_read(regs, decode.reg2);
> > +
> > +    switch ( inv_type )
> 
> There doesn't appear to be a second use of inv_type, and hence you can
> 
>     switch ( reg_read(regs, decode.reg2) )
> 
> and remove the local variable.

Okay.

> > +    {
> > +    case INVEPT_SINGLE_CONTEXT:
> > +    {
> > +        struct p2m_domain *p2m = vcpu_nestedhvm(current).nv_p2m;
> > +        if ( p2m )
> > +        {
> > +           p2m_flush(current, p2m);
> 
> And similarly you said you fixed all the white space issues.

Very strange,  and I will fix it. Thanks!
Xiantao


> Jan
> 
> > +            ept_sync_domain(p2m);
> > +        }
> > +        break;
> > +    }
> > +    case INVEPT_ALL_CONTEXT:
> > +        p2m_flush_nestedp2m(current->domain);
> > +        __invept(INVEPT_ALL_CONTEXT, 0, 0);
> > +        break;
> > +    default:
> > +        vmreturn(regs, VMFAIL_INVALID);
> > +        return X86EMUL_OKAY;
> > +    }
> > +    vmreturn(regs, VMSUCCEED);
> > +    return X86EMUL_OKAY;
> > +}
> > +
> > +
> >  #define __emul_value(enable1, default1) \
> >      ((enable1 | default1) << 32 | (default1))
> >
> 


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