So, I am doing this on an AMD system and I have SE working and am able to get FS entering into virtualized mode. However, in FS I get an early exception while the kernel is booting. This seems a bit different from what Nilay and Adrian observed for FS. Could you please share the diffs that got FS working?
Thanks, Alex -----Original Message----- From: gem5-dev [mailto:gem5-dev-boun...@gem5.org] On Behalf Of Gabe Black via gem5-dev Sent: Tuesday, December 09, 2014 6:07 PM To: gem5 Developer List Subject: Re: [gem5-dev] x86 SE kvm functionality (AMD vs Intel) Oh, I see you have FS working again and not SE. NM, I'll keep looking. Gabe On Tue, Dec 9, 2014 at 4:04 PM, Gabe Black <gabebl...@google.com> wrote: > I have FS working again which is good, but I'm still having problems > with SE. If you could let me know what you did to get things going > that would be very helpful. > > Gabe > > On Tue, Dec 9, 2014 at 10:06 AM, Dutu, Alexandru via gem5-dev < > gem5-dev@gem5.org> wrote: > >> Hi Adrian, >> >> Sorry for missing your first email. I do see the interchanged segment >> limits for full system mode, though I get a different behaviour on my >> system. The simulation seems to hang in the following manner: >> >> Processor #0 (Bootup-CPU) >> I/O APIC #1 at 0xFEC00000. >> Setting APIC routing to flat >> Processors: 1 >> PANIC: early exception rip ffffffff807909a9 error 9 cr2 >> ffffffffff5fd020 >> >> Can please provide a patch with all the modifications that fixed the >> issue on your system? >> >> Thank you, >> Alex >> ________________________________________ >> From: gem5-dev [gem5-dev-boun...@gem5.org] on behalf of Adrián Colaso >> Diego via gem5-dev [gem5-dev@gem5.org] >> Sent: Tuesday, December 09, 2014 2:09 AM >> To: gem5 Developer List >> Subject: Re: [gem5-dev] x86 SE kvm functionality (AMD vs Intel) >> >> You are right Nilay. I sent an email last week but nobody has replied. >> >> It seems that descriptors (cdDesc, dsDesc and tssDesc) located in >> src/arch/x86/system.cc file are not well-initialized and as a >> consequence kvm does not work when running in full-system mode. >> >> Segment limits values (limitHigh and limitLow) are interchanged and >> several segment descriptor values are wrong too. If these values are >> corrected kvm works again as before. >> >> Adrian >> >> El lun, 08-12-2014 a las 22:50 -0600, Nilay Vaish via gem5-dev escribió: >> > I also faced problem in getting KVM CPU to run in FS mode. I >> > figured >> that >> > the following changeset causes problems: >> > >> > author Alexandru Dutu <alexandru.d...@amd.com> >> > Sun Nov 23 18:01:08 2014 -0800 (2 weeks ago) >> > changeset 10554 fe2e2f06a7c8 >> > >> > I saw the hardware reason 0x80000021, but did not try to figure >> > what was going on wrong. >> > >> > -- >> > Nilay >> > >> > On Mon, 8 Dec 2014, Gabe Black via gem5-dev wrote: >> > >> > > I'm pretty sure entering 64 bit mode is the same between AMD and >> > > Intel CPUs. I vaguely remember there being some subtle page table >> > > difference though, and gem5 is building the page tables in SE >> > > mode instead of the kernel. >> > > >> > > Gabe >> > > >> > > On Mon, Dec 8, 2014 at 7:44 PM, Dutu, Alexandru via gem5-dev < >> > > gem5-dev@gem5.org> wrote: >> > > >> > >> Hi Mike, >> > >> >> > >> trace-cmd is a very handy tool to get an overview of what the >> > >> kvm >> kernel >> > >> module is doing before going into gdb. In extreme cases ftrace >> > >> can be useful as well. >> > >> What is the error that you are seeing? Is it still failing to >> > >> enter virtualized mode? >> > >> >> > >> If that is the case and the hardware reason is 0x80000021, that >> seems to >> > >> be an unrecoverable exception (drivers/hv/hyperv_vmbus.h in >> > >> linux >> kernel >> > >> source code). When running in SE mode, we are trying to bring >> > >> the >> machine >> > >> state to full 64bit mode without going through legacy modes. It >> might be >> > >> that Intel machines have a different way of going to 64bit mode >> > >> than >> AMD >> > >> machines (different CR4, different way of enabling 64bit mode >> > >> page >> tables >> > >> etc.). I remember dealing with these issue for AMD platforms by >> > >> going through System Programming manual and making sure gem5 >> > >> gets all the >> bits >> > >> right as there is not much the KVM kernel model will tell about >> > >> the >> cause >> > >> of failure. >> > >> >> > >> Best regards, >> > >> Alex >> > >> ________________________________________ >> > >> From: gem5-dev [gem5-dev-boun...@gem5.org] on behalf of Gabe >> > >> Black >> via >> > >> gem5-dev [gem5-dev@gem5.org] >> > >> Sent: Monday, December 08, 2014 7:08 PM >> > >> To: gem5 Developer List >> > >> Subject: Re: [gem5-dev] x86 SE kvm functionality (AMD vs Intel) >> > >> >> > >> I'm not an expert either, but I did have problems running KVM in >> > >> SE >> mode on >> > >> an Intel CPU. I didn't look into it that much, but I think >> > >> things >> failed in >> > >> the kernel somewhere. What might be happening is that the >> > >> different >> vendors >> > >> hardware virtualization mechanisms are more or less picky about >> various >> > >> things. Something might be set up incorrectly, and one >> implementation gets >> > >> more upset about it than the other. I believe there are tools >> > >> which >> will >> > >> help you determine whether your VM state is legal. Perhaps >> > >> Andreas >> can tell >> > >> you more about those? >> > >> >> > >> Gabe >> > >> >> > >> On Mon, Dec 8, 2014 at 4:29 PM, mike upton via gem5-dev < >> gem5-dev@gem5.org >> > >>> >> > >> wrote: >> > >> >> > >>> I have verified that x86 kvm works fine on AMD platforms, but >> > >>> fails >> on >> > >>> Intel platforms. >> > >>> >> > >>> Any hints about how to narrow down the cause (other than diving >> into gdb, >> > >>> which I will do). >> > >>> >> > >>> I am not an expert in KVM or how gem5 hooks up to libkvm. >> > >>> _______________________________________________ >> > >>> gem5-dev mailing list >> > >>> gem5-dev@gem5.org >> > >>> http://m5sim.org/mailman/listinfo/gem5-dev >> > >>> >> > >> _______________________________________________ >> > >> gem5-dev mailing list >> > >> gem5-dev@gem5.org >> > >> http://m5sim.org/mailman/listinfo/gem5-dev >> > >> _______________________________________________ >> > >> gem5-dev mailing list >> > >> gem5-dev@gem5.org >> > >> http://m5sim.org/mailman/listinfo/gem5-dev >> > >> >> > > _______________________________________________ >> > > gem5-dev mailing list >> > > gem5-dev@gem5.org >> > > http://m5sim.org/mailman/listinfo/gem5-dev >> > > >> > _______________________________________________ >> > gem5-dev mailing list >> > gem5-dev@gem5.org >> > http://m5sim.org/mailman/listinfo/gem5-dev >> >> >> _______________________________________________ >> gem5-dev mailing list >> gem5-dev@gem5.org >> http://m5sim.org/mailman/listinfo/gem5-dev >> _______________________________________________ >> gem5-dev mailing list >> gem5-dev@gem5.org >> http://m5sim.org/mailman/listinfo/gem5-dev >> > > _______________________________________________ gem5-dev mailing list gem5-dev@gem5.org http://m5sim.org/mailman/listinfo/gem5-dev _______________________________________________ gem5-dev mailing list gem5-dev@gem5.org http://m5sim.org/mailman/listinfo/gem5-dev
