Hi Adrian, Sorry for missing your first email. I have solved the interchanged segment limits and other bits in segment descriptors for full system mode, though I get a different behavior 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 you please provide a patch with all the modifications that fixed the issue on your system? Thank you, Alex -----Original Message----- From: gem5-dev [mailto:gem5-dev-boun...@gem5.org] On Behalf Of mike upton via gem5-dev Sent: Tuesday, December 09, 2014 11:52 AM To: gem5 Developer List Subject: Re: [gem5-dev] x86 SE kvm functionality (AMD vs Intel) Will someone be providing a patch for this? I am happy to test it. From Adrian's description it seems there are a bunch of issues. On Tue, Dec 9, 2014 at 12:09 AM, Adrián Colaso Diego via gem5-dev < gem5-dev@gem5.org> wrote: > 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
