Re: [PATCH 2/5] iommu/x86: print RMRR/IVMD ranges using full addresses

From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
	Paul Durrant <paul@xen.org>,
	xen-devel@lists.xenproject.org
Subject: Re: [PATCH 2/5] iommu/x86: print RMRR/IVMD ranges using full addresses
Date: Wed, 14 Feb 2024 15:03:55 +0100	[thread overview]
Message-ID: <ZczIS7Rlnt0xeVGF@macbook> (raw)
In-Reply-To: <2416e41e-0b59-4e63-a9c2-550983b71c1c@suse.com>

On Wed, Feb 14, 2024 at 02:22:09PM +0100, Jan Beulich wrote:
> On 14.02.2024 11:37, Roger Pau Monne wrote:
> > It's easier to correlate with the physical memory map if the addresses are
> > fully printed, instead of using frame numbers.
> > 
> > Requested-by: Andrew Cooper <andrew.cooper3@citrix.com>
> > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> 
> In principle
> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> I'm not sure though that this fully matches Andrew's intentions:
> 
> > --- a/xen/drivers/passthrough/x86/iommu.c
> > +++ b/xen/drivers/passthrough/x86/iommu.c
> > @@ -801,8 +801,8 @@ bool __init iommu_unity_region_ok(const char *prefix, mfn_t start, mfn_t end)
> >          return true;
> >  
> >      printk(XENLOG_WARNING
> > -           "%s: [%#" PRI_mfn " ,%#" PRI_mfn "] is not (entirely) in reserved memory\n",
> > -           prefix, mfn_x(start), mfn_x(end));
> > +           "%s: [%#lx, %#lx] is not (entirely) in reserved memory\n",
> > +           prefix, mfn_to_maddr(start), mfn_to_maddr(end));
> 
> e820.c uses [%016Lx, %016Lx] instead, i.e. full 16-digit numbers. For
> easiest cross matching it may be desirable to do the same here. Then
> of course the 0x prefixes may also better disappear.

Yes, I also saw that format, but wasn't sure whether it was desirable
to use here, as for example I would expect RMRR/IVMD regions to be
below the 4GB boundary.  Also the leading zeros are useful to have a
uniform table when printing the memory map that contains more than
one entry, but here I expect printing will be limited to a very small
set of entries, or maybe just one (as we only print the misplaced
ones).

Thanks, Roger.