Re: [Qemu-devel] [kvm-unit-tests PATCH v7 00/11] QEMU MTTCG Test cases

[Andrew Jones]

On Thu, Nov 24, 2016 at 04:10:22PM +0000, Alex Bennée wrote:
> Hi,
> 
> Looking at my records it seems as though it has been a while since I
> last posted these tests. As I'm hoping to get the final bits of MTTCG
> merged upstream on the next QEMU development cycle I've been re-basing
> these and getting them cleaned up for merging.
> 
> Some of the patches might be worth taking now if the maintainers are
> happy to do so (run_test tweaks, libcflat updates?). The others could
> do with more serious review. I've CC'd some of the ARM guys to look
> over the tlbflush/barrier tests so they can cast their expert eyes
> over them ;-)
> 
> There are two additions to the series.
> 
> The tcg-test is a general torture test aimed at QEMU's TCG execution
> model. It stresses the cpu execution loop through the use of
> cross-page and computed jumps. It can also add IRQ's and self-modifying
> code to the mix.
> 
> The tlbflush-data test is a new one, the old tlbflush test is renamed
> tlbflush-code to better indicate the code path it exercise. The the
> code test tests the translation invalidation pathways in QEMU the data
> test exercises the SoftMMU's TLBs and explicitly that tlbflush
> completion semantics are correct.
> 
> The tlbflush-data passes most of the times on real hardware but
> definitely showed the problem with deferred TLB flushes running under
> MTTCG QEMU. I've looked at some of the failure cases on real hardware
> and it did look like a timestamp appeared on a page that shouldn't
> have been accessible at the time - I don't know if this is a real
> silicon bug or my misreading of the semantics so I'd appreciate
> a comment from the experts.
> 
> The code needs to be applied on top of Drew's latest ARM GIC patches
> or you can grab my tree from:
> 
>   https://github.com/stsquad/kvm-unit-tests/tree/mttcg/current-tests-v7

Thanks Alex,

I've skimmed over everything looking at it from a framwork/sytle
perspective. I didn't dig in trying to understand the tests though.
One general comment, I see many tests introduce MAX_CPUS 8. Why do
that? Why not allow all cpus by using NR_CPUS for the array sizes?

Thanks,
drew

> 
> Cheers,
> 
> Alex.
> 
> Alex Bennée (11):
>   run_tests: allow forcing of acceleration mode
>   run_tests: allow disabling of timeouts
>   run_tests: allow passing of options to QEMU
>   libcflat: add PRI(dux)32 format types
>   lib: add isaac prng library from CCAN
>   arm/Makefile.common: force -fno-pic
>   arm/tlbflush-code: Add TLB flush during code execution test
>   arm/tlbflush-data: Add TLB flush during data writes test
>   arm/locking-tests: add comprehensive locking test
>   arm/barrier-litmus-tests: add simple mp and sal litmus tests
>   arm/tcg-test: some basic TCG exercising tests
> 
>  Makefile                  |   2 +
>  arm/Makefile.arm          |   2 +
>  arm/Makefile.arm64        |   2 +
>  arm/Makefile.common       |  11 ++
>  arm/barrier-litmus-test.c | 437 
> ++++++++++++++++++++++++++++++++++++++++++++++
>  arm/locking-test.c        | 302 ++++++++++++++++++++++++++++++++
>  arm/tcg-test-asm.S        | 170 ++++++++++++++++++
>  arm/tcg-test-asm64.S      | 169 ++++++++++++++++++
>  arm/tcg-test.c            | 337 +++++++++++++++++++++++++++++++++++
>  arm/tlbflush-code.c       | 212 ++++++++++++++++++++++
>  arm/tlbflush-data.c       | 401 ++++++++++++++++++++++++++++++++++++++++++
>  arm/unittests.cfg         | 190 ++++++++++++++++++++
>  lib/arm/asm/barrier.h     |  63 ++++++-
>  lib/arm64/asm/barrier.h   |  50 ++++++
>  lib/libcflat.h            |   5 +
>  lib/prng.c                | 162 +++++++++++++++++
>  lib/prng.h                |  82 +++++++++
>  run_tests.sh              |  18 +-
>  scripts/functions.bash    |  13 +-
>  scripts/runtime.bash      |   8 +
>  20 files changed, 2626 insertions(+), 10 deletions(-)
>  create mode 100644 arm/barrier-litmus-test.c
>  create mode 100644 arm/locking-test.c
>  create mode 100644 arm/tcg-test-asm.S
>  create mode 100644 arm/tcg-test-asm64.S
>  create mode 100644 arm/tcg-test.c
>  create mode 100644 arm/tlbflush-code.c
>  create mode 100644 arm/tlbflush-data.c
>  create mode 100644 lib/prng.c
>  create mode 100644 lib/prng.h
> 
> -- 
> 2.10.1
> 
>