Re: NetBSD 7.1 amd64 boot failure on KVM

[coypu%sdf.org@localhost]

On Sat, May 20, 2017 at 06:06:06PM +0300, Andrei M. wrote:
> Hello all,
> 
> I've encountered a problem with running NetBSD 7.1 as guest on
> KVM/qemu as experienced previously with 7.0:
> 
> https://mail-index.netbsd.org/netbsd-users/2015/12/31/msg017550.html
> 
> The output is practically the same, even the same values for registers:
> 
> vmt0 at cpu0: Unknown
> vmware: open failed, eax=564d5868, ecx=0000001e, edx=00005658
> vmt0: failed to open backdoor RPC channel (TCLO protocol)
> 
> Host machine - Linux Ubuntu 64 bit, qemu-kvm 1:2.5+dfsg-5ubunbtu10.14,
> the guest machine (NetBSD 7.1) run through Virtual Machine Manager.
> I've tried different memory values, between 512 MB and 1.5 GB (I
> wasn't allowed to set more, even though my PC has 4GB), with the same
> result.
> 
> The output refers to the following lines in NetBSD/sys/arch/x86/x86/vmt.c:
> 
> 306 vmt_attach (device_t parent, device_t self, void *aux):
> ...
> 336 if (vm_rpc_open(&sc->sc_tclo_rpc, VM_RPC_OPEN_TCLO) != 0) {
> 337        aprint_error_dev(self, "failed to open backdoor RPC channel
> (TCLO protocol)\n");
> 338        goto free;
> 339    }
> 
> http://bxr.su/NetBSD/sys/arch/x86/x86/vmt.c
> 
> Andrei

You could sync with openbsd vmt. it will fix the 'backdoor RPC channel',
but userconf disable vmt will achieve the same - qemu claims to support
enough to pass this but does not.