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Re: kvm errors with 4.9.0-9 kernel.




Good Day John,

I tried to reproduce the problem on my side, using KVM
accelerated with the module kvm_intel from Debian native kernel
4.9.0-9-amd64 #1 SMP Debian 4.9.168-1+deb9u2 (2019-05-13).

I encountered the following trace in my `dmesg` output, which is
only remotely related to kvm_intel:

	[   89.389480] kvm: zapping shadow pages for mmio generation wraparound
	[  120.924745] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x1c9
	[  120.928959] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x1a6
	[  120.933429] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x1a7
	[  120.938123] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x3f6
	[  120.942968] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x3f7
	[  120.971155] kvm: zapping shadow pages for mmio generation wraparound
	[  121.498463] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x64e
	[  121.503585] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x34
	[  125.592208] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x606
	[  126.334166] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x611
	[  126.339807] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x639
	[  126.345627] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x641
	[  126.351708] kvm [1716]: vcpu0, guest rIP: 0xffffffffaea5a602 unhandled rdmsr: 0x619

While you were seeing:
> > >	[    6.234764] kvm_intel: Unknown symbol cpu_tlbstate (err -22)
> > >	[    6.235463] kvm_intel: Unknown symbol mds_user_clear (err 0)
> > >	[    6.330732] kvm_intel: disagrees about version of symbol cpu_tlbstate

On my side, my messages did not prove to be fatal.  I have been
able to start virtual machines.

Using upstream kernel 4.19.45 on another machine did not show
any issues at all.  I don't know if that could be eligible to
additional material or not to the bug report (well if you
issued one :).  I thought it might have been worth mentioning
anyway.

Perhaps the CPU model has it's importance, I used an Intel Xeon
W-2104 for my test with the native Debian kernel, and an Intel
i7 of 7th generation for my test with upstream kernel.

Kind Regards,
-- 
Étienne Mollier <etienne.mollier@xxxxxxxxxx>