linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v2 0/4] KVM: arm/arm64: vgic: Use raw_spinlock for locks taken in IRQ context
@ 2018-11-26 18:26 Julien Thierry
  2018-11-26 18:26 ` [PATCH v2 1/4] KVM: arm/arm64: vgic: Do not cond_resched_lock() with IRQs disabled Julien Thierry
                   ` (3 more replies)
  0 siblings, 4 replies; 8+ messages in thread
From: Julien Thierry @ 2018-11-26 18:26 UTC (permalink / raw)
  To: linux-kernel, kvmarm
  Cc: marc.zyngier, Christoffer.Dall, linux-arm-kernel, linux-rt-users,
	tglx, rostedt, bigeasy, Julien Thierry

Hi,

While testing KVM running on PREEMPT_RT, starting guest could simply
freeze the machine. This is because we are using spinlocks for VGIC
locks, which is invalid in the VGIC case since the locks must be take
with interrupts disabled.

The solution is to use raw_spinlock instead of spinlocks.

Replacing those locks also highlighted an issue where we attempt to
cond_resched with interrupts disabled.

Patch 1 fixes the cond_resched issue.
Patch 2-4 replace the VGIC spinlocks with raw_spinlocks

Changes since v1[1]:
- Rebase on v4.20-rc4
- Add Christoffer's Acked-by
- Fix potential lock up when waiting for vcpus to halt

[1] https://lkml.org/lkml/2018/11/19/776

Cheers,

Julien

-->

Julien Thierry (4):
  KVM: arm/arm64: vgic: Do not cond_resched_lock() with IRQs disabled
  KVM: arm/arm64: vgic: Make vgic_irq->irq_lock a raw_spinlock
  KVM: arm/arm64: vgic: Make vgic_dist->lpi_list_lock a raw_spinlock
  KVM: arm/arm64: vgic: Make vgic_cpu->ap_list_lock a raw_spinlock

 include/kvm/arm_vgic.h           |   6 +-
 virt/kvm/arm/vgic/vgic-debug.c   |   4 +-
 virt/kvm/arm/vgic/vgic-init.c    |   8 +--
 virt/kvm/arm/vgic/vgic-its.c     |  22 +++----
 virt/kvm/arm/vgic/vgic-mmio-v2.c |  14 ++---
 virt/kvm/arm/vgic/vgic-mmio-v3.c |  12 ++--
 virt/kvm/arm/vgic/vgic-mmio.c    |  70 ++++++++++-----------
 virt/kvm/arm/vgic/vgic-v2.c      |   4 +-
 virt/kvm/arm/vgic/vgic-v3.c      |   8 +--
 virt/kvm/arm/vgic/vgic.c         | 130 +++++++++++++++++++--------------------
 10 files changed, 135 insertions(+), 143 deletions(-)

--
1.9.1

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2018-12-14  9:37 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-11-26 18:26 [PATCH v2 0/4] KVM: arm/arm64: vgic: Use raw_spinlock for locks taken in IRQ context Julien Thierry
2018-11-26 18:26 ` [PATCH v2 1/4] KVM: arm/arm64: vgic: Do not cond_resched_lock() with IRQs disabled Julien Thierry
2018-12-11 10:20   ` Christoffer Dall
2018-12-14  9:36     ` Julien Thierry
2018-11-26 18:26 ` [PATCH v2 2/4] KVM: arm/arm64: vgic: Make vgic_irq->irq_lock a raw_spinlock Julien Thierry
2018-11-26 18:26 ` [PATCH v2 3/4] KVM: arm/arm64: vgic: Make vgic_dist->lpi_list_lock " Julien Thierry
2018-11-26 18:26 ` [PATCH v2 4/4] KVM: arm/arm64: vgic: Make vgic_cpu->ap_list_lock " Julien Thierry
2018-12-11 10:32   ` Christoffer Dall

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).