From mboxrd@z Thu Jan 1 00:00:00 1970 From: cdall@linaro.org (Christoffer Dall) Date: Wed, 22 Feb 2017 13:27:14 +0100 Subject: [RFC 25/55] KVM: arm/arm64: Let vcpu thread modify its own active state In-Reply-To: <1483943091-1364-26-git-send-email-jintack@cs.columbia.edu> References: <1483943091-1364-1-git-send-email-jintack@cs.columbia.edu> <1483943091-1364-26-git-send-email-jintack@cs.columbia.edu> Message-ID: <20170222122714.GN26976@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jan 09, 2017 at 01:24:21AM -0500, Jintack Lim wrote: > Currently, if a vcpu thread tries to change its own active state when > the irq is already in AP list, it'll loop forever. Since the VCPU thread > has already synced back LR state to the struct vgic_irq, let it modify > its own state safely. > > Signed-off-by: Jintack Lim > --- > virt/kvm/arm/vgic/vgic-mmio.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c > index ebe1b9f..049c570 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio.c > +++ b/virt/kvm/arm/vgic/vgic-mmio.c > @@ -192,9 +192,9 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq, > * If this virtual IRQ was written into a list register, we > * have to make sure the CPU that runs the VCPU thread has > * synced back LR state to the struct vgic_irq. We can only > - * know this for sure, when either this irq is not assigned to > + * know this for sure, when this irq is not assigned to > * anyone's AP list anymore, or the VCPU thread is not > - * running on any CPUs. > + * running on any CPUs, or current thread is the VCPU thread. > * > * In the opposite case, we know the VCPU thread may be on its > * way back from the guest and still has to sync back this > @@ -202,6 +202,7 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq, > * other thread sync back the IRQ. > */ > while (irq->vcpu && /* IRQ may have state in an LR somewhere */ > + irq->vcpu != vcpu && /* Current thread is not the VCPU thread */ > irq->vcpu->cpu != -1) /* VCPU thread is running */ > cond_resched_lock(&irq->irq_lock); > > -- > 1.9.1 > > This seems to be an independent fix, so please send it outside of this series as an individual patch. Thanks, -Christoffer