From bd2be6836ee493d41fe42367a2b129aa771185c1 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Mon, 13 Aug 2012 01:04:19 +0200 Subject: KVM: PPC: Book3S: PR: Rework irq disabling Today, we disable preemption while inside guest context, because we need to expose to the world that we are not in a preemptible context. However, during that time we already have interrupts disabled, which would indicate that we are in a non-preemptible context. The reason the checks for irqs_disabled() fail for us though is that we manually control hard IRQs and ignore all the lazy EE framework. Let's stop doing that. Instead, let's always use lazy EE to indicate when we want to disable IRQs, but do a special final switch that gets us into EE disabled, but soft enabled state. That way when we get back out of guest state, we are immediately ready to process interrupts. This simplifies the code drastically and reduces the time that we appear as preempt disabled. Signed-off-by: Alexander Graf --- arch/powerpc/kvm/powerpc.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'arch/powerpc/kvm/powerpc.c') diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 153a26abc91..266549979e9 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -30,6 +30,7 @@ #include #include #include +#include #include "timing.h" #include "../mm/mmu_decl.h" @@ -93,6 +94,19 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) break; } +#ifdef CONFIG_PPC64 + /* lazy EE magic */ + hard_irq_disable(); + if (lazy_irq_pending()) { + /* Got an interrupt in between, try again */ + local_irq_enable(); + local_irq_disable(); + continue; + } + + trace_hardirqs_on(); +#endif + /* Going into guest context! Yay! */ vcpu->mode = IN_GUEST_MODE; smp_wmb(); -- cgit v1.2.3-70-g09d2