From: Christoffer Dall Date: Mon, 4 May 2015 01:25:16 +0000 (+0800) Subject: arm/arm64: KVM: Initialize the vgic on-demand when injecting IRQs X-Git-Tag: v3.18.14~210 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=11d483cec89a33c6fc1bdd08901b0da723d6f2b9;p=thirdparty%2Fkernel%2Fstable.git arm/arm64: KVM: Initialize the vgic on-demand when injecting IRQs commit ca7d9c829d419c06e450afa5f785d58198c37caa upstream. Userspace assumes that it can wire up IRQ injections after having created all VCPUs and after having created the VGIC, but potentially before starting the first VCPU. This can currently lead to lost IRQs because the state of that IRQ injection is not stored anywhere and we don't return an error to userspace. We haven't seen this problem manifest itself yet, presumably because guests reset the devices on boot, but this could cause issues with migration and other non-standard startup configurations. Reviewed-by: Marc Zyngier Signed-off-by: Christoffer Dall Signed-off-by: Shannon Zhao Signed-off-by: Sasha Levin --- diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 12c10f26901f6..9a8c18301b7a4 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1693,16 +1693,26 @@ out: int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num, bool level) { + int ret = 0; int vcpu_id; - if (likely(vgic_initialized(kvm))) { - vcpu_id = vgic_update_irq_pending(kvm, cpuid, irq_num, level); - if (vcpu_id >= 0) - /* kick the specified vcpu */ - kvm_vcpu_kick(kvm_get_vcpu(kvm, vcpu_id)); + if (unlikely(!vgic_initialized(kvm))) { + mutex_lock(&kvm->lock); + ret = vgic_init(kvm); + mutex_unlock(&kvm->lock); + + if (ret) + goto out; } - return 0; + vcpu_id = vgic_update_irq_pending(kvm, cpuid, irq_num, level); + if (vcpu_id >= 0) { + /* kick the specified vcpu */ + kvm_vcpu_kick(kvm_get_vcpu(kvm, vcpu_id)); + } + +out: + return ret; } static irqreturn_t vgic_maintenance_handler(int irq, void *data)