Re: [PATCH v5 1/3] x86/iommu: remove regions not to be mapped

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Thu, Jan 25, 2024 at 12:13:01PM +0100, Jan Beulich wrote:
> On 25.01.2024 09:47, Roger Pau Monné wrote:
> > On Thu, Jan 25, 2024 at 09:34:40AM +0100, Jan Beulich wrote:
> >> On 24.01.2024 18:29, Roger Pau Monne wrote:
> >>> --- a/xen/arch/x86/hvm/io.c
> >>> +++ b/xen/arch/x86/hvm/io.c
> >>> @@ -369,6 +369,22 @@ bool vpci_is_mmcfg_address(const struct domain *d, 
> >>> paddr_t addr)
> >>>      return vpci_mmcfg_find(d, addr);
> >>>  }
> >>>  
> >>> +int __hwdom_init vpci_subtract_mmcfg(const struct domain *d, struct 
> >>> rangeset *r)
> >>> +{
> >>> +    const struct hvm_mmcfg *mmcfg;
> >>> +
> >>> +    list_for_each_entry ( mmcfg, &d->arch.hvm.mmcfg_regions, next )
> >>> +    {
> >>> +        int rc = rangeset_remove_range(r, PFN_DOWN(mmcfg->addr),
> >>> +                                       PFN_DOWN(mmcfg->addr + 
> >>> mmcfg->size - 1));
> >>
> >> Along the lines of this, ...
> >>
> >>> --- a/xen/arch/x86/setup.c
> >>> +++ b/xen/arch/x86/setup.c
> >>> @@ -2138,6 +2138,54 @@ int __hwdom_init xen_in_range(unsigned long mfn)
> >>>      return 0;
> >>>  }
> >>>  
> >>> +int __hwdom_init remove_xen_ranges(struct rangeset *r)
> >>> +{
> >>> +    paddr_t start, end;
> >>> +    int rc;
> >>> +
> >>> +    /* S3 resume code (and other real mode trampoline code) */
> >>> +    rc = rangeset_remove_range(r, 
> >>> PFN_DOWN(bootsym_phys(trampoline_start)),
> >>> +                               PFN_DOWN(bootsym_phys(trampoline_end)) - 
> >>> 1);
> >>
> >> ... did you perhaps mean
> >>
> >>                                PFN_DOWN(bootsym_phys(trampoline_end) - 1));
> >>
> >> here (and then similarly below, except there the difference is benign I
> >> think, for the labels being page-aligned)?
> > 
> > They are all page aligned, so I didn't care much,  but now that you
> > point it might be safer to do the subtraction from the address instead
> > of the frame number, just in case.
> 
> Hmm, no, for me neither trampoline_end nor trampoline_start are page
> aligned. While bootsym_phys(trampoline_start) is, I don't think
> bootsym_phys(trampoline_end) normally would be (it might only be by
> coincidence).

Oh, so it had been a coincidence of the build I was using I guess then.

Thanks, Roger.