[v2,0/3] powerpc/xive: Fix race condition leading to host crashes and hangs

Message

Paul Mackerras Aug. 13, 2019, 9:58 a.m. UTC

This series fixes a race condition that has been observed in testing
on POWER9 machines running KVM guests.  An interrupt being freed by
free_irq() can have an instance present in a XIVE interrupt queue,
which can then be presented to the generic interrupt code after the
data structures for it have been freed, leading to a variety of
crashes and hangs.

This series is based on current upstream kernel source plus Cédric Le
Goater's patch "KVM: PPC: Book3S HV: XIVE: Free escalation interrupts
before disabling the VP", which is a pre-requisite for this series.
As it touches both KVM and generic PPC code, this series will probably
go in via Michael Ellerman's powerpc tree.

V2 of this patch series adds a patch fixing a bug noticed by Cédric,
and also fixes a bug in patch 1/2 of the v1 series.

Paul.

 arch/powerpc/include/asm/xive.h         |  8 +++
 arch/powerpc/kvm/book3s_hv_rmhandlers.S | 38 +++++++++-----
 arch/powerpc/kvm/book3s_xive.c          | 42 +++++++++++++++-
 arch/powerpc/kvm/book3s_xive.h          |  2 +
 arch/powerpc/kvm/book3s_xive_native.c   |  6 +++
 arch/powerpc/sysdev/xive/common.c       | 87 ++++++++++++++++++++++++---------
 6 files changed, 146 insertions(+), 37 deletions(-)