Re: Xen 4.4.2, coverage does not work properly

[zithro <slack@xxxxxxxxx>]

On 02 May 2023 14:23, Giuseppe De Rosa wrote:
> Hello everybody,
>
> I apologize for asking for help on such an outdated version of Xen. I would 
> like to understand why xencov read always returns the same dat file as shown in 
> the attached file.
>
> I followed this guide 
> https://wiki.xenproject.org/index.php?title=Compiling_Xen_From_Source&oldid=17237
>  (14 September 2016 version) to compile Xen from source and this guide to enable 
> coverage support https://xenbits.xen.org/docs/4.8-testing/misc/coverage.html. I 
> also applied this patch 
> https://lists.xenproject.org/archives/html/xen-devel/2016-08/msg03353.html because 
> I had some compilation errors.
>
> Everything went fine until I used xencov read. The result is always the same (4 
> bytes returned, always .CTX) but the file is malformed because xencov_split 
> cannot read that.
>
> I am using Ubuntu 14.04. I made sure to enable test coverage support under 
> xen/Config.mk and gcov under tools/qemu-xen/configure. I checked the 
> compilation logs and every file was instrumented with the -ftest-coverage 
> option.
Maybe look for more 4.4 bug reports about coverage, as another patch is 
needed ?
I found that they almost totally rewrote coverage in 4.7.

The current man page about coverage 
(https://xenbits.xen.org/docs/unstable/hypervisor-guide/code-coverage.html) 
is a bit different.
"enable CONFIG_COVERAGE in Kconfig".
(mentionned in 
"https://lists.xenproject.org/archives/html/xen-devel/2016-08/msg03363.html";).
There's also "xencov reset".

But honestly this is above me. Maybe try the xen-devel ML ?

PS: at first I thought your post was a prank, but no, just discovered 
"xl li == xl lis == xl list" ! Why not "xl l" though ^^