[0/2] powerpc/xive: Fix race condition leading to host crashes and hangs

Message

Paul Mackerras Aug. 12, 2019, 5:06 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.

Paul.

 arch/powerpc/include/asm/xive.h         |  8 +++
 arch/powerpc/kvm/book3s_hv_rmhandlers.S | 23 ++++++---
 arch/powerpc/kvm/book3s_xive.c          | 31 ++++++++++++
 arch/powerpc/sysdev/xive/common.c       | 87 ++++++++++++++++++++++++---------
 4 files changed, 119 insertions(+), 30 deletions(-)