linux-kernel - [PATCH 0/4] KVM: selftests: Introduce VM_MODE_PXXV48

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Message-Id: <20190827131015.21691-1-peterx@redhat.com>
Date:   Tue, 27 Aug 2019 21:10:11 +0800
From:   Peter Xu <peterx@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Thomas Huth <thuth@...hat.com>,
        Andrew Jones <drjones@...hat.com>, peterx@...hat.com
Subject: [PATCH 0/4] KVM: selftests: Introduce VM_MODE_PXXV48_4K

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" [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.

Any kind of smoke test would be greatly welcomed (especially on s390
or ARM).  Same to comments.  Thanks,

[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  | 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(-)

-- 
2.21.0