Hi, Isaku and Tristan
Thank you for your comments.
>
>On Thu, Oct 05, 2006 at 04:55:07PM +0900, Isaku Yamahata wrote:
>> On Thu, Oct 05, 2006 at 04:00:20PM +0900, Akio Takebe wrote:
>> > Hi,
>> >
>> > Also in the case of current Xen-ia64-unstable(cset:11721),
>> > this panic is occured by specified dom0_mem=4G.
>> > (without my patch)
>> >
>> > I think the following error message is hint of this bug.
>> > (XEN) Warning: UC to WB for mpaddr=f9ff0000
>> >
>> > I checked the arch/ia64/xen/mm.c
>> > Why changing pteval2 from UC to WB is OK?
>> > If pteval2 is WB and pteval is UC, should pteval2 be changed to UC?
>> >
>>
>> Because it's RAM. not I/O.
>> >From your log
>> > (XEN) dom mem: type= 7, attr=0x0000000000000008, range=
>> > [0x0000000080000000-0x00000000fe000000) (2016MB)
>> Probably ioremap hypercall failed.
>> Please check it by adding debug message assign_domain_same_page().
>> I suppose it should complain somehow.
>>
>>
>> The warning message is the result of Linux tries to use the addresses
>> for I/O which is RAM.
>> Then the next question is why/how Linux decided to use the addresses
>> to map I/O.
>> iomem_resource manages those regions so that such a overlap
>> shouldn't happen.
>
>This is wrong. Linux doesn't complain.
>Dom0 builder assigns RAM which overlaps with PCI I/O so that
>dom0Linux can't access PCI devices.
>So far no one has assigned so much memory to dom0,
>this wasn't an issue.
Thank you for your infomation!.
I checked Linux /proc/iomem. You are right.
# cat /proc/iomem
[snip..]
f8e00000-f8efffff : 0000:06:02.1
f8fc0000-f8fcffff : 0000:06:02.0
f8fd0000-f8fdffff : 0000:06:02.0
f8fe0000-f8feffff : 0000:06:02.1
f8ff0000-f8ffffff : 0000:06:02.1
f9000000-fbffffff : PCI Bus 0000:00 <-----------this
f9ff0000-f9ff03ff : 0000:00:1d.7
f9ff0000-f9ff03ff : ehci_hcd
fa000000-fbffffff : PCI Bus #01
fa000000-faffffff : 0000:01:01.0
And the below is dom0 map at dom0_mem=2G and dom0_mem=4G.
dom0_mem=4G
(XEN) dom mem: type=13, attr=0x8000000000000008,
range=[0x0000000000000000-0x0000000000001000) (4KB)
(XEN) dom mem: type=10, attr=0x8000000000000008,
range=[0x0000000000001000-0x0000000000002000) (4KB)
(XEN) dom mem: type= 6, attr=0x8000000000000008,
range=[0x0000000000002000-0x0000000000003000) (4KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000003000-0x0000000000007000) (16KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000007000-0x0000000000009000) (8KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000009000-0x0000000000082000) (484KB)
(XEN) dom mem: type= 6, attr=0x8000000000000009,
range=[0x0000000000082000-0x0000000000084000) (8KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000084000-0x0000000000085000) (4KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000085000-0x00000000000a0000) (108KB)
(XEN) dom mem: type= 5, attr=0x8000000000000009,
range=[0x00000000000c0000-0x0000000000100000) (256KB)
(XEN) dom mem: type= 7, attr=0x0000000000000008,
range=[0x0000000000100000-0x000000007f708000) (2038MB)
(XEN) dom mem: type= 5, attr=0x8000000000000009,
range=[0x000000007f70a000-0x000000007fb00000) (3MB)
(XEN) dom mem: type= 7, attr=0x0000000000000008,
range=[0x000000007fb00000-0x000000007fe00000) (3MB)
(XEN) dom mem: type= 5, attr=0x8000000000000009,
range=[0x000000007fe00000-0x000000007fe58000) (352KB)
(XEN) dom mem: type= 7, attr=0x0000000000000008,
range=[0x000000007fe58000-0x000000007feb8000) (384KB)
(XEN) dom mem: type= 6, attr=0x8000000000000009,
range=[0x000000007feba000-0x0000000080000000) (1MB)
(XEN) dom mem: type= 7, attr=0x0000000000000008,
range=[0x0000000080000000-0x00000000fe000000) (2016MB)
(XEN) dom mem: type=11, attr=0x0000000000000001,
range=[0x00000000fe000000-0x00000000ff000000) (16MB)
(XEN) dom mem: type= 6, attr=0x8000000000000001,
range=[0x00000000ff000000-0x0000000100000000) (16MB)
(XEN) dom mem: type= 6, attr=0x8000000000000009,
range=[0x00000001ffffe000-0x0000000200000000) (8KB)
(XEN) dom mem: type= 5, attr=0x8000000000000009,
range=[0x00000002ffe14000-0x00000002ffe80000) (432KB)
(XEN) dom mem: type= 6, attr=0x8000000000000009,
range=[0x00000002fffb8000-0x0000000300000000) (288KB)
(XEN) dom mem: type=11, attr=0x8000000000000001,
range=[0x00000ffff8000000-0x00000ffffc000000) (64MB)
(XEN) dom mem: type=12, attr=0x8000000000000001,
range=[0x00000ffffc000000-0x0000100000000000) (64MB)
dom0_mem=2G
(XEN) dom mem: type=13, attr=0x8000000000000008,
range=[0x0000000000000000-0x0000000000001000) (4KB)
(XEN) dom mem: type=10, attr=0x8000000000000008,
range=[0x0000000000001000-0x0000000000002000) (4KB)
(XEN) dom mem: type= 6, attr=0x8000000000000008,
range=[0x0000000000002000-0x0000000000003000) (4KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000003000-0x0000000000007000) (16KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000007000-0x0000000000009000) (8KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000009000-0x0000000000082000) (484KB)
(XEN) dom mem: type= 6, attr=0x8000000000000009,
range=[0x0000000000082000-0x0000000000084000) (8KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000084000-0x0000000000085000) (4KB)
(XEN) dom mem: type= 7, attr=0x0000000000000009,
range=[0x0000000000085000-0x00000000000a0000) (108KB)
(XEN) dom mem: type= 5, attr=0x8000000000000009,
range=[0x00000000000c0000-0x0000000000100000) (256KB)
(XEN) dom mem: type= 7, attr=0x0000000000000008,
range=[0x0000000000100000-0x000000007f708000) (2038MB)
(XEN) dom mem: type= 5, attr=0x8000000000000009,
range=[0x000000007f70a000-0x000000007fb00000) (3MB)
(XEN) dom mem: type= 7, attr=0x0000000000000008,
range=[0x000000007fb00000-0x000000007fe00000) (3MB)
(XEN) dom mem: type= 5, attr=0x8000000000000009,
range=[0x000000007fe00000-0x000000007fe58000) (352KB)
(XEN) dom mem: type= 7, attr=0x0000000000000008,
range=[0x000000007fe58000-0x000000007feb8000) (384KB)
(XEN) dom mem: type= 6, attr=0x8000000000000009,
range=[0x000000007feba000-0x0000000080000000) (1MB)
(XEN) dom mem: type=11, attr=0x0000000000000001,
range=[0x00000000fe000000-0x00000000ff000000) (16MB)
(XEN) dom mem: type= 6, attr=0x8000000000000001,
range=[0x00000000ff000000-0x0000000100000000) (16MB)
(XEN) dom mem: type= 6, attr=0x8000000000000009,
range=[0x00000001ffffe000-0x0000000200000000) (8KB)
(XEN) dom mem: type= 5, attr=0x8000000000000009,
range=[0x00000002ffe14000-0x00000002ffe80000) (432KB)
(XEN) dom mem: type= 6, attr=0x8000000000000009,
range=[0x00000002fffb8000-0x0000000300000000) (288KB)
(XEN) dom mem: type=11, attr=0x8000000000000001,
range=[0x00000ffff8000000-0x00000ffffc000000) (64MB)
(XEN) dom mem: type=12, attr=0x8000000000000001,
range=[0x00000ffffc000000-0x0000100000000000) (64MB)
>
>I think there are two right way.
>A avoid overlap somehow
> A.0 fake up ACPI table and assign pci somewhere.
> A.1 detect pci bridge
> To detect the region of pci bridge, it is necessary to parse
> ACPI table. But xen doesn't have such a ACPI parser.
> A.2 As a temporal work around, we can introduce xen boot option to
> indicate pci io area.
> A.3 assign RAM following the original MD.
> This might be easy.
> The current complete_dom0_memmap() seeks a gap and fill it
> with RAM. modify it so that it only assigns RAM only when
> a found gap is in baremetal's RAM.
>B modify ioremap hypercall and linux ioremap somehow
> to not use ram region.
> Probably Linux ioremap() wouldn't return __IA64_UNCACHED_OFFSET|offset
> so that iounmap() might need to be implemented.
>C don't give so much memory to dom0
> The original motivation is to get modular vnif work.
> Now xencomm has been merged, this isn't an issue anymore.
> Akio, Is this right?
>
Yes, you are right.
I have not tried to check modular vnif yet.
But I have checked it with cset 11635 + Tristan's xen-xcom-[a-c]3.diffs.
The results is good work.
>Option C or A.3 is preferable. I don't think those are
>ery good, though. Any ideas?
>
I also prefer A.3 to others.
Best Regards,
Akio Takebe
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