Re: [PATCH v2 0/4] KVM: selftests: Introduce VM_MODE_PXXV48_4K

Andrew Jones
2019-08-29T16:46:49Z

On Thu, Aug 29, 2019 at 10:21:13AM +0800, Peter Xu wrote:
> v2:
> - pick r-bs
> - rebased to master
> - fix pa width detect, check cpuid(1):edx.PAE(bit 6)
> - fix arm compilation issue [Drew]
> - fix indents issues and ways to define macros [Drew]
> - provide functions for fetching cpu pa/va bits [Drew]
>
> This series originates from "[PATCH] KVM: selftests: Detect max PA
> width from cpuid" [1] and one of Drew's comments - instead of keeping
> the hackish line to overwrite guest_pa_bits all the time, this series
> introduced the new mode VM_MODE_PXXV48_4K for x86_64 platform.
>
> The major issue is that even all the x86_64 kvm selftests are
> currently using the guest mode VM_MODE_P52V48_4K, many x86_64 hosts
> are not using 52 bits PA (and in most cases, far less). If with luck
> we could be having 48 bits hosts, but it's more adhoc (I've observed 3
> x86_64 systems, they are having different PA width of 36, 39, 48). I
> am not sure whether this is happening to the other archs as well, but
> it probably makes sense to bring the x86_64 tests to the real world on
> always using the correct PA bits.
>
> A side effect of this series is that it will also fix the crash we've
> encountered on Xeon E3-1220 as mentioned [1] due to the
> differenciation of PA width.
>
> With [1], we've observed AMD host issues when with NPT=off. However a
> funny fact is that after I reworked into this series, the tests can
> instead pass on both NPT=on/off. It could be that the series changes
> vm->pa_bits or other fields so something was affected. I didn't dig
> more on that though, considering we should not lose anything.
>
> [1] https://lkml.org/lkml/2019/8/26/141
>
> Peter Xu (4):
> KVM: selftests: Move vm type into _vm_create() internally
> KVM: selftests: Create VM earlier for dirty log test
> KVM: selftests: Introduce VM_MODE_PXXV48_4K
> KVM: selftests: Remove duplicate guest mode handling
>
> tools/testing/selftests/kvm/dirty_log_test.c | 79 +++++--------------
> .../testing/selftests/kvm/include/kvm_util.h | 16 +++-
> .../selftests/kvm/include/x86_64/processor.h | 3 +
> .../selftests/kvm/lib/aarch64/processor.c | 3 +
> tools/testing/selftests/kvm/lib/kvm_util.c | 67 ++++++++++++----
> .../selftests/kvm/lib/x86_64/processor.c | 30 ++++++-
> 6 files changed, 119 insertions(+), 79 deletions(-)
>
> --
> 2.21.0
>

Tested on AArch64. Looks good.

Thanks,
drew