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
