Re: [PATCH 0/4] KVM: selftests: Introduce VM_MODE_PXXV48_4K
From: Andrew Jones
Date: Wed Aug 28 2019 - 07:51:15 EST
On Tue, Aug 27, 2019 at 09:10:11PM +0800, Peter Xu wrote:
> The work is based on Thomas's s390 port for dirty_log_test.
> This series originates from "[PATCH] KVM: selftests: Detect max PA
> width from cpuid"  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  due to the
> differenciation of PA width.
> With , 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.
> Any kind of smoke test would be greatly welcomed (especially on s390
> or ARM). Same to comments. Thanks,
The patches didn't apply cleanly for me on 9e8312f5e160, but once I got
them applied I was able to run the aarch64 tests.
>  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 | 78 +++++--------------
> .../testing/selftests/kvm/include/kvm_util.h | 17 +++-
> .../selftests/kvm/lib/aarch64/processor.c | 3 +
> tools/testing/selftests/kvm/lib/kvm_util.c | 77 ++++++++++++++----
> .../selftests/kvm/lib/x86_64/processor.c | 8 +-
> 5 files changed, 107 insertions(+), 76 deletions(-)