Re: [Xen-devel] [PATCH 0 of 5] update xenctx to dump pagetables

[Olaf Hering <olaf@xxxxxxxxx>]

On Tue, Jun 21, Jan Beulich wrote:

> >>> On 21.06.11 at 11:59, Tim Deegan <Tim.Deegan@xxxxxxxxxx> wrote:
> > Hi, 
> > 
> > At 17:56 -0400 on 20 Jun (1308592583), Konrad Rzeszutek Wilk wrote:
> >> > Any ideas why some mfns are not accessible?
> >> 
> >> They look to be the special I/O PFNs. The ones that cover ACPI, 
> >> framebuffer,
> >> PCI IO bars, MP tale.
> > 
> > I think they're too high for that, but if you can post the e820 map of
> > the system this happened on then we'll know. 
> > 
> >> > Are there any other paging states maintained outside of the guests
> >> > memory?
> >> 
> >> They look to be I/O pages.
> >> 
> >> But not sure why they are mapped to your guest?
> > 
> > But they're not mapped into the guest - from the look of them they're
> > not mapped anywhere.  You could add some extra printouts around that
> > warning in mm.c to show whether the MFNs are valid and if so which
> > domain owns them.
> > 
> > Also, interesting that it's the addresses just above 0xffff800000000000
> > that are different - what lives at that address in the PV kernel you're
> > running?
> 
> That's Xen's space, isn't it. Clearly any non-hypervisor based page
> table walking code has to ignore this range for PV guests' page
> tables.

Is there a way to detect that? I cant seem to match any of these ranges to
something in guests dmesg or /proc.

After adding some debug to my xenctx from sles11 4.0, I get this on vcpu 0:

xc_map_foreign_range: walk_l3: 0 virt 0000800000000000 mfn 13fff8: Invalid 
argument
xc_map_foreign_range: walk_l3: 0 virt 0000808000000000 mfn 13fff0: Invalid 
argument
xc_map_foreign_range: walk_l2: 0 virt 0000814000000000 mfn 13fff8: Invalid 
argument
xc_map_foreign_range: walk_l2: 0 virt 0000814040000000 mfn 13fff0: Invalid 
argument
xc_map_foreign_range: walk_l1: 0 virt 00008140a0000000 mfn 13fff8: Invalid 
argument
xc_map_foreign_range: walk_l1: 0 virt 00008140a0200000 mfn 13fff0: Invalid 
argument
xc_map_foreign_range: walk_l1: 0 virt 00008140a0800000 mfn 137ff8: Invalid 
argument
xc_map_foreign_range: walk_l1: 0 virt 00008140a0a00000 mfn bf49a: Invalid 
argument
xc_map_foreign_range: walk_l1: 0 virt 00008140a0c00000 mfn bf495: Invalid 
argument
xc_map_foreign_range: walk_l2: 0 virt 0000814100000000 mfn 137ff8: Invalid 
argument
xc_map_foreign_range: walk_l2: 0 virt 0000814140000000 mfn bf49a: Invalid 
argument
xc_map_foreign_range: walk_l2: 0 virt 0000814180000000 mfn bf495: Invalid 
argument
xc_map_foreign_range: walk_l3: 0 virt 0000820000000000 mfn 137ff8: Invalid 
argument
xc_map_foreign_range: walk_l3: 0 virt 0000828000000000 mfn bf49a: Invalid 
argument
xc_map_foreign_range: walk_l3: 0 virt 0000830000000000 mfn bf495: Invalid 
argument


And dmesg has:

(XEN) mm.c:880:d0 Error getting mfn 13fff8 (pfn 5555555555555555) from L1 entry 
800000013fff8625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn 13fff0 (pfn 5555555555555555) from L1 entry 
800000013fff0625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn 13fff8 (pfn 5555555555555555) from L1 entry 
800000013fff8625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn 13fff0 (pfn 5555555555555555) from L1 entry 
800000013fff0625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn 13fff8 (pfn 5555555555555555) from L1 entry 
800000013fff8625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn 13fff0 (pfn 5555555555555555) from L1 entry 
800000013fff0625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn 137ff8 (pfn f180d) from L1 entry 
8000000137ff8625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn bf49a (pfn 5555555555555555) from L1 entry 
80000000bf49a625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn bf495 (pfn 5555555555555555) from L1 entry 
80000000bf495625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn 137ff8 (pfn f180d) from L1 entry 
8000000137ff8625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn bf49a (pfn 5555555555555555) from L1 entry 
80000000bf49a625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn bf495 (pfn 5555555555555555) from L1 entry 
80000000bf495625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn 137ff8 (pfn f180d) from L1 entry 
8000000137ff8625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn bf49a (pfn 5555555555555555) from L1 entry 
80000000bf49a625 for l1e_owner=0, pg_owner=1
(XEN) mm.c:880:d0 Error getting mfn bf495 (pfn 5555555555555555) from L1 entry 
80000000bf495625 for l1e_owner=0, pg_owner=1

Olaf

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