Re: [PATCH resend] qemuboot.conf: make cpus match built artifacts

[Randy Witt <randy.e.witt@linux.intel.com>]

On 05/22/2017 10:29 AM, Martin Kelly wrote:
> (friendly ping)
> 
> On 05/02/2017 12:20 PM, Martin Kelly wrote:
>> Currently, the qemu CPUs for are specified as generic, but the built
>> artifacts are not. For example, we build x86-64 artifacts targeting
>> core2duo but run them in qemu with generic qemu/kvm CPUs. This causes
>> some packages that take advantage of the host architecture to crash
>> because they try to use CPU features not advertised by qemu. As an
>> example, Qt uses ssse3. When artifacts linked against Qt and built
>> targeting core2duo attempt to run on a generic qemu/kvm CPU, we get
>> the following crash:
>>
>> Incompatible processor. This Qt build requires the following features:
>>      ssse3
>>
>> We could fix this by making packages like Qt not take advantage of CPU
>> features. However, we will probably keep facing similar issues over
>> time, so it's better to resolve them in a more enduring way.

If the MACHINE is a generic qemu, it seems more correct to build without the 
extensions. For instance, what happens when core2duo doesn't have all the 
necessary instructions that some package decided to use?

I like the idea of being able to exercise the code, but I only see this fix as 
pushing the maintenance until the problem appears again later.

>>
>> Fix this by making the qemu -cpu arguments match the built artifacts.
>>
>> Signed-off-by: Martin Kelly <mkelly@xevo.com>
>> ---
>>
>> I sent this to poky@yoctoproject.org but it should have gone to OE-core,
>> so I'm resending it now to restart the discussion on the right mailing
>> list. There were some comments about it in a previous mail thread on the
>> poky mailing list:
>>
>> https://lists.yoctoproject.org/pipermail/poky/2017-April/010956.html
>>
>>  meta/conf/machine/include/qemuboot-x86.inc | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/meta/conf/machine/include/qemuboot-x86.inc 
>> b/meta/conf/machine/include/qemuboot-x86.inc
>> index 06ac983..acd03a1 100644
>> --- a/meta/conf/machine/include/qemuboot-x86.inc
>> +++ b/meta/conf/machine/include/qemuboot-x86.inc
>> @@ -1,12 +1,12 @@
>>  # For runqemu
>>  IMAGE_CLASSES += "qemuboot"
>>  QB_SYSTEM_NAME_x86 = "qemu-system-i386"
>> -QB_CPU_x86 = "-cpu qemu32"
>> -QB_CPU_KVM_x86 = "-cpu kvm32"
>> +QB_CPU_x86 = "-cpu pentium2"
>> +QB_CPU_KVM_x86 = "-cpu pentium2"
>>
>>  QB_SYSTEM_NAME_x86-64 = "qemu-system-x86_64"
>>  QB_CPU_x86-64 = "-cpu core2duo"
>> -QB_CPU_KVM_x86-64 = "-cpu kvm64"
>> +QB_CPU_KVM_x86-64 = "-cpu core2duo"
>>
>>  QB_AUDIO_DRV = "alsa"
>>  QB_AUDIO_OPT = "-soundhw ac97,es1370"
>>