Hi Hassan,
Someone skilled in the assumptions of x86 memory layout may be able to help
you. I doubt there is an easy fix, but I could be wrong.
For ARM it should not be a problem to have this “segmented” memory. Currently
the gem5 ARM Linux System assumes a single range presented to the OS, but this
could easily be fixed (see LinuxArmSystem::initState). If you take the plunge
and go this route please share the patch on RB.
Thanks,
Andreas
From: Ahmad Hassan <[email protected]<mailto:[email protected]>>
Reply-To: gem5 users mailing list
<[email protected]<mailto:[email protected]>>
Date: Monday, 2 December 2013 16:18
To: gem5 users mailing list <[email protected]<mailto:[email protected]>>
Subject: Re: [gem5-users] Running two SimpleDram instances simulataniously
Hi Andreas,
Please may I ask if you are experiencing the similar errors if you define a
second main memory controller beyond IO physical address ranges? Would this be
happening or this is completely an undesired behavior?
If Linux always need contiguous physical address range for multiple memory
controllers then is it possible to move IO address range from 3GB start address
to something 128GB starting address and then define two main memory controllers
that share the physical address range of 0GB to 128GB to have 128 GB RAM
capacity please?
In another attempt, I tried to move the first main memory controller starting
from 0GB to 10GB but it doesn't work because linux is accessing memory between
0 to 128MB address range.
Thanks again for your help.
Best Regards, Hassan
On 28 November 2013 15:55, Ahmad Hassan
<[email protected]<mailto:[email protected]>> wrote:
Hi Andreas,
To make sure it is not caused by my local changes, I just cloned the fresh
revison 9644:07352f119e48 and defined two memory controllers as:
self.physmem = SimpleDDR3(range = AddrRange(start="0GB", size="2GB"))
self.physmem2 = SimpleDDR3(range = AddrRange(start="50GB",size="1GB"))
self.mem_ranges = [self.physmem.range,self.physmem2.range]
Again, I see the same error where linux boot-up fails while accessing physical
address: 3217031168. It seems that guest OS assumes that All 3GB space is
contiguous.
I don't know why it worked last week.
Thanks for the help.
Best Regards, Hassan
On 28 November 2013 14:50, Ahmad Hassan
<[email protected]<mailto:[email protected]>> wrote:
Hi Andreas,
I assume so. I get this 'segmentation fault' while booting linux:
./build/X86/gem5.opt configs/example/fs.py --kernel=x86_64-vmlinux-2.6.22.9.smp
But I think, I booted the linux last week with similar configuration and I
think it worked fine. It seems bit strange to me that I am seeing this
segmentation fault now.
Best Regards, Hassan
On 28 November 2013 13:53, Andreas Hansson
<[email protected]<mailto:[email protected]>> wrote:
Hi Hassan,
What is it that is assuming that the memory is contiguous? The guest OS?
Andreas
From: Ahmad Hassan <[email protected]<mailto:[email protected]>>
Reply-To: gem5 users mailing list
<[email protected]<mailto:[email protected]>>
Date: Thursday, 28 November 2013 06:43
To: gem5 users mailing list <[email protected]<mailto:[email protected]>>
Subject: Re: [gem5-users] Running two SimpleDram instances simulataniously
Hi Andreas,
I have defined two memory controllers:
self.dram2_ctl = SimpleDDR3(range = AddrRange(start='0MB',size='3GB'))
self.dram1_ctl = SimpleDDR3(range = AddrRange(start='10GB',size='16GB'))
But I am getting exception in findPort method where it raises because it tries
to access physical address 6438256672 for membus
DPRINTF(BusAddrRanges, "Unable to find destination for addr %#llx, "
"will use default port\n", addr);
As a result of that, I get segmentation fault during memcpy operation in
abstract_mem.cc:access
This error is happening because system is assuming that all the 19GB of
physical memory is contiguous. Please can you advise me how to fix this. Thanks.
Best Regards, Hassan
On 31 October 2013 18:00, Andreas Hansson
<[email protected]<mailto:[email protected]>> wrote:
Hi Ahmad,
If you change the bus code then every bus in the system will do this, including
the I/O bus. I suspect this is the reason for your error. You can keep on the
hackish path and add a name check to only do this for the membus (or add a
parameter to the bus and change the MemBus instance), or preferably get of the
hackish path and rely on physical addresses and sort out your “placement” by
assigning the appropriate physical addresses in your TLBs (or preferably in the
OS).
Red pill or blue pill.
Andreas
From: Ahmad Hassan <[email protected]<mailto:[email protected]>>
Reply-To: gem5 users mailing list
<[email protected]<mailto:[email protected]>>
Date: Thursday, 31 October 2013 16:51
To: gem5 users mailing list <[email protected]<mailto:[email protected]>>
Subject: Re: [gem5-users] Running two SimpleDram instances simulataniously
Hi Andreas,
In my system:
DDR3 memory controller: Port ID 0 //2GB capacity
DDR2 memory controller: Port ID 1 //1GB capacity
So I want to do the following:
When the packet comes into bus.cc:findPort then it searches for packet's
physical address in the registered portMap of address ranges and returns the
appropriate port ID. I don't want to do this. Instead, I want to select port
based on the virtual address. I have list of virtual addresses say V=[V1....Vn]
and I want to redirect all the packets with virtual address within set 'V' to
DDR3 Port 0 and all other memory packets to the DDR2 port 1.
In order to achieve this, I changed bus.cc:findPort as:
if (search(V, pkt->req->getVaddr()) == true)
dest_id = 0;
else
dest_id = 1;
After that, abstract_mem.cc:access complained that the packet address doesn't
belong to the range of PORT '1'. Just as a quick hack, I changed it as:
old: uint8_t *hostAddr = pmemAddr + pkt->getAddr() - range.start();
new: uint8_t *hostAddr = pmemAddr + pkt->getAddr() - 0; // Port ID 0 range
starts with '0'
Now the linux starts booting but during the half way, it throws this cmos
assertion. Please can you suggest the clean or right way of implementing what I
am trying to achieve.
Thanks a lot
kind Regards, Ahmad
On 31 October 2013 16:25, Andreas Hansson
<[email protected]<mailto:[email protected]>> wrote:
Hi Ahmad,
I could be wrong, but judging by your mail, I get the impression that you’re
overriding the address decoding. That is essentially saying “If I send requests
for address X to address Y, why do things not work?”. I would be very surprised
if it did, as two addresses will now map to the same location :-). Perhaps I’m
not understanding what you’ve changed.
Andreas
From: Ahmad Hassan <[email protected]<mailto:[email protected]>>
Reply-To: gem5 users mailing list
<[email protected]<mailto:[email protected]>>
Date: Thursday, 31 October 2013 16:12
To: gem5 users mailing list <[email protected]<mailto:[email protected]>>
Subject: Re: [gem5-users] Running two SimpleDram instances simulataniously
HI Andreas,
I have connected two memory controllers and I can see the following two port
IDs and their physical address ranges:
Adding range [0 : 2147483647] for id 0 system.membus // 2GB memory
Adding range [2147483648 : 3221225471] for id 1 system.membus //1GB
memroy
Inside findPort method of bus.cc, if I assign the packet of port id '0' to port
id '1' then I get the following assertion error. This happens in half way
through the linux boot up:
gem5.opt: build/X86/dev/x86/cmos.cc:70: virtual Tick
X86ISA::Cmos::write(PacketPtr): Assertion `pkt->getSize() == 1' failed.
Please do you know what is causing that? Also I had to disable assertion in
abstract memory which validates that the packet's physical address in with in
the range of memory controller.
Thanks.
kind Regards, Ahmad
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please notify the sender immediately and do not disclose the contents to any
other person, use it for any purpose, or store or copy the information in any
medium. Thank you.
ARM Limited, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, Registered
in England & Wales, Company No: 2557590
ARM Holdings plc, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ,
Registered in England & Wales, Company No: 2548782
_______________________________________________
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confidential and may also be privileged. If you are not the intended recipient,
please notify the sender immediately and do not disclose the contents to any
other person, use it for any purpose, or store or copy the information in any
medium. Thank you.
ARM Limited, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, Registered
in England & Wales, Company No: 2557590
ARM Holdings plc, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ,
Registered in England & Wales, Company No: 2548782_______________________________________________
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