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  1. May 20, 2023
    • Sean Christopherson's avatar
      KVM: Don't enable hardware after a restart/shutdown is initiated · e0ceec22
      Sean Christopherson authored 
      Reject hardware enabling, i.e. VM creation, if a restart/shutdown has
been initiated to avoid re-enabling hardware between kvm_reboot() and
machine_{halt,power_off,restart}().  The restart case is especially
problematic (for x86) as enabling VMX (or clearing GIF in KVM_RUN on
SVM) blocks INIT, which results in the restart/reboot hanging as BIOS
is unable to wake and rendezvous with APs.

Note, this bug, and the original issue that motivated the addition of
kvm_reboot(), is effectively limited to a forced reboot, e.g. `reboot -f`.
In a "normal" reboot, userspace will gracefully teardown userspace before
triggering the kernel reboot (modulo bugs, errors, etc), i.e. any process
that might do ioctl(KVM_CREATE_VM) is long gone.

Fixes: 8e1c1815

 ("KVM: VMX: Disable VMX when system shutdown")
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Acked-by: default avatarMarc Zyngier <maz@kernel.org>
Message-Id: <20230512233127.804012-3-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      e0ceec22
    • Sean Christopherson's avatar
      KVM: Use syscore_ops instead of reboot_notifier to hook restart/shutdown · 6735150b
      Sean Christopherson authored 
      

Use syscore_ops.shutdown to disable hardware virtualization during a
reboot instead of using the dedicated reboot_notifier so that KVM disables
virtualization _after_ system_state has been updated.  This will allow
fixing a race in KVM's handling of a forced reboot where KVM can end up
enabling hardware virtualization between kernel_restart_prepare() and
machine_restart().

Rename KVM's hook to match the syscore op to avoid any possible confusion
from wiring up a "reboot" helper to a "shutdown" hook (neither "shutdown
nor "reboot" is completely accurate as the hook handles both).

Opportunistically rewrite kvm_shutdown()'s comment to make it less VMX
specific, and to explain why kvm_rebooting exists.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Zenghui Yu <yuzenghui@huawei.com>
Cc: kvmarm@lists.linux.dev
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Atish Patra <atishp@atishpatra.org>
Cc: kvm-riscv@lists.infradead.org
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Acked-by: default avatarMarc Zyngier <maz@kernel.org>
Message-Id: <20230512233127.804012-2-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      6735150b
  3. May 18, 2023
    • Paolo Bonzini's avatar
      Merge tag 'kvmarm-fixes-6.4-1' of... · 39428f6e
      Paolo Bonzini authored 
      Merge tag 'kvmarm-fixes-6.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.4, take #1

- Plug a race in the stage-2 mapping code where the IPA and the PA
  would end up being out of sync

- Make better use of the bitmap API (bitmap_zero, bitmap_zalloc...)

- FP/SVE/SME documentation update, in the hope that this field
  becomes clearer...

- Add workaround for the usual Apple SEIS brokenness

- Random comment fixes
      39428f6e
  5. May 15, 2023
  7. May 14, 2023
  9. May 13, 2023