On Tue, Feb 12, 2013 at 04:21:13PM -0800, H. Peter Anvin wrote: > On 02/12/2013 04:16 PM, Borislav Petkov wrote: > > > >This family check is redundant, we're already in a 0x10 if-branch > >above. Boris had sent a second version which doesn't have that check: > >http://marc.info/?l=linux-kernel&m=135949774114910 but I don't know how this > >other version has gotten in. > > > >@hpa: maybe replace - patch is still at the top of tip:x86/cpu? > > > > I'll check with Ingo if that is doable. > > >>+ rdmsrl(MSR_AMD64_BU_CFG2, value); > >>+ value &= ~(1ULL << 24); > >>+ wrmsrl(MSR_AMD64_BU_CFG2, value); > >>+ } > >> } > >> > >> rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy); > > > >However, the more serious issue is that that same kernel #GPs when > >booted in kvm. It seems it cannot stomach that specific MSR, see the > >second "<-- trapping instruction" below and that BU_CFG2 MSR landing in > >%ecx in the line before that. > > > >Oh, and this happens only with the kvm executable (/usr/bin/kvm) in > >debian testing. If I use qemu from git, it passes over init_amd just > >fine. > > > >Hmmm.. > > > > It #GPs on an MSR, which tends to be a bug in the VMM; RDMSR/WRMSR > generally kick out to the VMM. There isn't a huge lot of work we > can do about that...
Yeah, kvm.ko which runs on the host says that it ignores this MSR: [160716.170333] kvm [29093]: vcpu0 unhandled rdmsr: 0xc001102a > I think Qemu defaults to ignoring unknown-to-it MSRs whereas maybe > kvmtool croaks? Pekka? Actually that's the qemu kvm thing you get from http://www.linux-kvm.org not the kvmtool. Let me add the kvm ML to CC. Guys, when I start the guest in kvm, it #GPs early when it tries to RDMSR 0xc001102a. Here's the oops message: http://marc.info/?l=linux-kernel&m=136071460803452 qemu-kvm is qemu-kvm (1.1.2+dfsg-5) from debian testing. Command line is: kvm -snapshot -gdb tcp::1234 -cpu phenom -hda /home/boris/kvm/debian/sid-x86_64.img -name "Debian x86_64:1235" -boot menu=off,order=c -m 2048 -localtime -net nic -net user,hostfwd=tcp::1235-:22 -usbdevice tablet -kernel /w/kernel/linux-2.6/arch/x86/boot/bzImage -append "vga=0 root=/dev/sda1 debug ignore_loglevel console=ttyS0,115200 console=tty0" -serial file:/home/boris/kvm/test-x86_64.log Any ideas? -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
