On Mon, Jan 08, 2018 at 19:06:43 +0800, Feng, Shaohe  wrote:

On 2018年01月05日 02:52, John Ferlan wrote:

On 12/17/2017 06:02 PM, Shaohe Feng wrote:

We can start qemu with a "cpu,+la57" to set 57-bit vitrual address
space. So VM can be aware that it need to enable 5-level paging.

Corresponding QEMU commits:
         al57 6c7c3c21f95dd9af8a0691c0dd29b07247984122
---
  src/cpu/cpu_map.xml | 3 +++
  1 file changed, 3 insertions(+)

I think if you go through history of cpu_map.xml changes you'll find
when a new feature is added there are tests added as well - this would
thus seemingly need a test adjustment as well.

Thanks John.
Will add tests.

Adding such test usually means you go to tests/cputestdata/ directory
and run "./cpu-gather.sh | ./cpu-parse.sh" which will produce several
data files. Then you add a new test case in tests/cputest.c for this new
CPU and regenerate the files with expected results. If you do this
before adding the new feature, the patch which will then add it will
nicely show the new feature gets added into the expected results of the
new CPU test.

Don't forget to install cpuid tool and make sure you have the latest
upstream qemu installed in the system.

Jirka

Hi Jirka,

I went through the tests/cputestdata/ directory and found it’s for defining features for different CPU models.

However, the la57 feature is not included in any current CPUs. So I think we can get waived for the tests changes?

I check la57 on my Haswell platform it show

$ qemu-system-x86_64 -enable-kvm  -cpu Haswell,+la57,check
warning: host doesn't support requested feature: CPUID.07H:ECX.la57 [bit 16]