From 296c19d0b4072dd9594daeec532563e56bddd119 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Sun, 15 Aug 2010 08:39:19 +0200 Subject: [PATCH] KVM: PPC: Don't put MSR_POW in MSR On Book3S a mtmsr with the MSR_POW bit set indicates that the OS is in idle and only needs to be waked up on the next interrupt. Now, unfortunately we let that bit slip into the stored MSR value which is not what the real CPU does, so that we ended up executing code like this: r = mfmsr(); /* r containts MSR_POW */ mtmsr(r | MSR_EE); This obviously breaks, as we're going into idle mode in code sections that don't expect to be idling. This patch masks MSR_POW out of the stored MSR value on wakeup, making guests happy again. Signed-off-by: Alexander Graf --- arch/powerpc/kvm/book3s.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index 7adea6320654..5833df7e8ccc 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -134,10 +134,14 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u64 msr) vcpu->arch.shared->msr = msr; kvmppc_recalc_shadow_msr(vcpu); - if (msr & (MSR_WE|MSR_POW)) { + if (msr & MSR_POW) { if (!vcpu->arch.pending_exceptions) { kvm_vcpu_block(vcpu); vcpu->stat.halt_wakeup++; + + /* Unset POW bit after we woke up */ + msr &= ~MSR_POW; + vcpu->arch.shared->msr = msr; } }