Re: [Qemu-devel] [QEMU-1.6 & QEMU-Upstream PATCH] vl.c: Output error on invalid machine type provided

[Michal Novotny <minovotn@redhat.com>]

On 09/05/2013 01:39 PM, Daniel P. Berrange wrote:
> On Thu, Sep 05, 2013 at 01:36:09PM +0200, Michal Novotny wrote:
>> Output error message using qemu's error_report() function when user
>> provides the invalid machine type on the command line. This also saves
>> time to find what issue is when you downgrade from one version of qemu
>> to another that doesn't support required machine type yet (the version
>> user downgraded to have to have this patch applied too, of course).
>>
>> (This has been posted a while ago and reviewed however not applied yet
>>  so this is basically just a reminder e-mail to ask for pushing it.
>>  It also applies cleanly to QEMU-1.6 so I'm sending to qemu-stable as
>>  well.)
>>
>> Signed-off-by: Michal Novotny <minovotn@redhat.com>
>> ---
>>  vl.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/vl.c b/vl.c
>> index f422a1c..9b4a3f9 100644
>> --- a/vl.c
>> +++ b/vl.c
>> @@ -2671,6 +2671,11 @@ static QEMUMachine *machine_parse(const char *name)
>>      if (machine) {
>>          return machine;
>>      }
>> +
>> +    if (name && !is_help_option(name)) {
>> +        error_report("Unsupported machine type");
>> +    }
> It would be nicer to do
>
>      error_report("Unsupported machine type '%s'", name);

No need Daniel, as the output is having this already (as mentioned by
Markus in the previous thread):

$ ./x86_64-softmmu/qemu-system-x86_64 -M bogus
-M bogus: Unsupported machine type
$

So the CLI arguments are in the beginning of the line already. If we
consider long CLI args, like:

$ ./x86_64-softmmu/qemu-system-x86_64 -S -M bogus -cpu
core2duo,+lahf_lm,+rdtscp,+avx,+osxsave,+xsave,+aes,+tsc-deadline,+popcnt,+x2apic,+sse4.2,+sse4.1,+pdcm,+xtpr,+cx16,+tm2,+est,+smx,+vmx,+ds_cpl,+dtes64,+pclmuldq,+pbe,+tm,+ht,+ss,+acpi,+ds
-enable-kvm -m 1024 -smp 1,sockets=1,cores=1,threads=1 -name debian
-uuid 374677db-d9b1-3326-a097-5f2b79d3fca0 -nodefconfig -nodefaults
-chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/debian.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc
-no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2
-device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x4 -device
lsi,id=scsi0,bus=pci.0,addr=0x7 -drive
if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw -device
ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive
file=/home/mig/images/kvm/debian.qcow2,if=none,id=drive-virtio-disk0,format=qcow2
-device
virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1
-netdev tap,fd=20,id=hostnet0 -device
rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:4d:d9:c9,bus=pci.0,addr=0x3
-chardev pty,id=charserial0 -device
isa-serial,chardev=charserial0,id=serial0 -chardev
spicevmc,id=charchannel0,name=vdagent -device
virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0
-device usb-tablet,id=input0 -spice
port=5900,addr=127.0.0.1,disable-ticketing -vga qxl -global
qxl-vga.vram_size=67108864 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6

then it can make sense, however to change it from:

-S -M bogus -cpu
core2duo,+lahf_lm,+rdtscp,+avx,+osxsave,+xsave,+aes,+tsc-deadline,+popcnt,+x2apic,+sse4.2,+sse4.1,+pdcm,+xtpr,+cx16,+tm2,+est,+smx,+vmx,+ds_cpl,+dtes64,+pclmuldq,+pbe,+tm,+ht,+ss,+acpi,+ds
-enable-kvm -m 1024 -smp 1,sockets=1,cores=1,threads=1 -name debian
-uuid 374677db-d9b1-3326-a097-5f2b79d3fca0 -nodefconfig -nodefaults
-chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/debian.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc
-no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2
-device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x4 -device
lsi,id=scsi0,bus=pci.0,addr=0x7 -drive
if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw -device
ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive
file=/home/mig/images/kvm/debian.qcow2,if=none,id=drive-virtio-disk0,format=qcow2
-device
virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1
-netdev tap,fd=20,id=hostnet0 -device
rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:4d:d9:c9,bus=pci.0,addr=0x3
-chardev pty,id=charserial0 -device
isa-serial,chardev=charserial0,id=serial0 -chardev
spicevmc,id=charchannel0,name=vdagent -device
virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0
-device usb-tablet,id=input0 -spice
port=5900,addr=127.0.0.1,disable-ticketing -vga qxl -global
qxl-vga.vram_size=67108864 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6: Unsupported machine type

to:

-S -M bogus -cpu
core2duo,+lahf_lm,+rdtscp,+avx,+osxsave,+xsave,+aes,+tsc-deadline,+popcnt,+x2apic,+sse4.2,+sse4.1,+pdcm,+xtpr,+cx16,+tm2,+est,+smx,+vmx,+ds_cpl,+dtes64,+pclmuldq,+pbe,+tm,+ht,+ss,+acpi,+ds
-enable-kvm -m 1024 -smp 1,sockets=1,cores=1,threads=1 -name debian
-uuid 374677db-d9b1-3326-a097-5f2b79d3fca0 -nodefconfig -nodefaults
-chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/debian.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc
-no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2
-device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x4 -device
lsi,id=scsi0,bus=pci.0,addr=0x7 -drive
if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw -device
ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive
file=/home/mig/images/kvm/debian.qcow2,if=none,id=drive-virtio-disk0,format=qcow2
-device
virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1
-netdev tap,fd=20,id=hostnet0 -device
rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:4d:d9:c9,bus=pci.0,addr=0x3
-chardev pty,id=charserial0 -device
isa-serial,chardev=charserial0,id=serial0 -chardev
spicevmc,id=charchannel0,name=vdagent -device
virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0
-device usb-tablet,id=input0 -spice
port=5900,addr=127.0.0.1,disable-ticketing -vga qxl -global
qxl-vga.vram_size=67108864 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6: Unsupported machine
type 'bogus'

In this case, however, I would like to prefer not to show all the
arguments and to stick with standalone printf() printing just:

-M bogus: Unsupported machine type

using:

fprintf(stderr, "-M %s: Unsupported machine type\n", type);

What do you think?

Michal
>
>
> So when people report error messages in bugs / mailing lists, without
> providing their CLI args, it'll be obvious what they requested.
>
> Daniel

-- 
Michal Novotny <minovotn@redhat.com>, RHCE, Red Hat
Virtualization | libvirt-php bindings | php-virt-control.org