# BISECT LOG

git bisect start
# bad: [0adb32858b0bddf4ada5f364a84ed60b196dbcda] Linux 4.16
git bisect bad 0adb32858b0bddf4ada5f364a84ed60b196dbcda
# good: [d8a5b80568a9cb66810e75b182018e9edb68e8ff] Linux 4.15
git bisect good d8a5b80568a9cb66810e75b182018e9edb68e8ff
# good: [c14376de3a1befa70d9811ca2872d47367b48767] printk: Wake klogd when 
passing console_lock owner
git bisect good c14376de3a1befa70d9811ca2872d47367b48767
# good: [2246edfaf88dc368e8671b04afd54412625df60a] Merge tag 'for-linus' of 
git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
git bisect good 2246edfaf88dc368e8671b04afd54412625df60a
# good: [dfe8db22372873d205c78a9fd5370b1b088a2b87] Merge tag 
'drm-misc-fixes-2018-02-21' of git://anongit.freedesktop.org/drm/drm-misc into 
drm-fixes
git bisect good dfe8db22372873d205c78a9fd5370b1b088a2b87
# bad: [4665c6b04651e96c1e2eb9129a30d6055040ff73] Merge tag 
'linux-can-fixes-for-4.16-20180312' of 
ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can
git bisect bad 4665c6b04651e96c1e2eb9129a30d6055040ff73
# bad: [3499de32fa6b608ba646380ac3838d30a2558ead] Merge tag 
'linux-kselftest-4.16-rc4' of 
git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
git bisect bad 3499de32fa6b608ba646380ac3838d30a2558ead
# good: [65738c6b461a8bb0b056e024299738f7cc9a28b7] Merge tag 'arm64-fixes' of 
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
git bisect good 65738c6b461a8bb0b056e024299738f7cc9a28b7
# good: [c23a75759191e84f4ba15b85ea4f97bd544b5362] Merge branch 
'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect good c23a75759191e84f4ba15b85ea4f97bd544b5362
# bad: [d4858aaf6bd8a90e2dacc0dfec2077e334dcedbf] Merge tag 'for-linus' of 
git://git.kernel.org/pub/scm/virt/kvm/kvm
git bisect bad d4858aaf6bd8a90e2dacc0dfec2077e334dcedbf
# good: [0eb578009a1d530a11846d7c4733a5db04730884] tools/kvm_stat: use a more 
pythonic way to iterate over dictionaries
git bisect good 0eb578009a1d530a11846d7c4733a5db04730884
# good: [fe2a3027e74e40a3ece3a4c1e4e51403090a907a] KVM: x86: fix backward 
migration with async_PF
git bisect good fe2a3027e74e40a3ece3a4c1e4e51403090a907a
# bad: [7607b7174405aec7441ff6c970833c463114040a] KVM: SVM: install RSM 
intercept
git bisect bad 7607b7174405aec7441ff6c970833c463114040a
# good: [e5699f56bc91a286f006b0728085e0b4e8f5749b] crypto: ccp: Fix sparse, use 
plain integer as NULL pointer
git bisect good e5699f56bc91a286f006b0728085e0b4e8f5749b
# good: [3e233385ef4a217a2812115ed84d4be36eb16817] KVM: SVM: no need to call 
access_ok() in LAUNCH_MEASURE command
git bisect good 3e233385ef4a217a2812115ed84d4be36eb16817
# first bad commit: [7607b7174405aec7441ff6c970833c463114040a] KVM: SVM: 
install RSM intercept

# NOTE

I was doing "invert" bisection.. so the bad commit is actually what
seems to have fixed the issue:

commit 7607b7174405aec7441ff6c970833c463114040a
Author: Brijesh Singh <brijesh.si...@amd.com>
Date:   Mon Feb 19 10:14:44 2018 -0600

    KVM: SVM: install RSM intercept

    RSM instruction is used by the SMM handler to return from SMM mode.
    Currently, rsm causes a #UD - which results in instruction fetch, decode,
    and emulate. By installing the RSM intercept we can avoid the instruction
    fetch since we know that #VMEXIT was due to rsm.

    The patch is required for the SEV guest, because in case of SEV guest
    memory is encrypted with guest-specific key and hypervisor will not
    able to fetch the instruction bytes from the guest memory.

    Cc: Paolo Bonzini <pbonz...@redhat.com>
    Cc: Radim Krčmář <rkrc...@redhat.com>
    Cc: Joerg Roedel <j...@8bytes.org>
    Cc: Borislav Petkov <b...@suse.de>
    Cc: Tom Lendacky <thomas.lenda...@amd.com>
    Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
    Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1834522

Title:
  Bionic QEMU with Bionic Kernel hangs in AMD FX-8350 with cpu-host as
  passthrough

Status in linux package in Ubuntu:
  Fix Released
Status in linux source package in Bionic:
  In Progress

Bug description:
  [Impact]

   * QEMU does not work in some AMD hardware when using host-passthrough as 
cpu-mode (usually to allow nested KVM to work).
   * QEMU does not start, hanging before the VM initialization.

  [Test Case]

   * to use Xenial qemu on top of a regular Xenial kernel -> doesn't work 
(intermittent)
   * to use the following XML file: https://paste.ubuntu.com/p/BSyFY7ksR5/
   * to have AMD FX(tm)-8350 Eight-Core Processor CPU or similar
   * to use Xenial qemu on top of a HWE kernel -> works

  [Regression Potential]

   * TODO

  [Other Info]

   * TODO

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1834522/+subscriptions

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