RE: Ping: [PATCH] VT-d: fix !HVM build

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Jan Beulich <jbeulich@xxxxxxxx>
> Sent: Thursday, May 19, 2022 8:20 PM
> 
> On 22.04.2022 11:58, Jan Beulich wrote:
> > EPT is of no interest when !HVM. While I'm observing gcc11 to fully
> > eliminate the function, older gcc's DCE looks to not be as good. Aid the
> > compiler in eliminating the accesses of opt_hap_{2mb,1gb}, which
> > otherwise cause undefined symbol errors when linking.
> >
> > While there adjust types.
> >
> > Fixes: c479415610f0 ("x86/P2M: p2m.c is HVM-only")
> > Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> I guess I'll put this in (as being simple enough) if I don't hear
> anything back by the end of the week.

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>

> 
> Jan
> 
> > --- a/xen/drivers/passthrough/vtd/iommu.c
> > +++ b/xen/drivers/passthrough/vtd/iommu.c
> > @@ -2155,14 +2155,17 @@ static int cf_check intel_iommu_lookup_p
> >      return 0;
> >  }
> >
> > -static int __init vtd_ept_page_compatible(struct vtd_iommu *iommu)
> > +static bool __init vtd_ept_page_compatible(const struct vtd_iommu
> *iommu)
> >  {
> > -    u64 ept_cap, vtd_cap = iommu->cap;
> > +    uint64_t ept_cap, vtd_cap = iommu->cap;
> > +
> > +    if ( !IS_ENABLED(CONFIG_HVM) )
> > +        return false;
> >
> >      /* EPT is not initialised yet, so we must check the capability in
> >       * the MSR explicitly rather than use cpu_has_vmx_ept_*() */
> >      if ( rdmsr_safe(MSR_IA32_VMX_EPT_VPID_CAP, ept_cap) != 0 )
> > -        return 0;
> > +        return false;
> >
> >      return (ept_has_2mb(ept_cap) && opt_hap_2mb) <=
> cap_sps_2mb(vtd_cap) &&
> >             (ept_has_1gb(ept_cap) && opt_hap_1gb) <= cap_sps_1gb(vtd_cap);
> >
> >