path: root/virt/kvm
diff options
authorChristoffer Dall <christoffer.dall@linaro.org>2013-09-23 14:55:55 -0700
committerChristoffer Dall <christoffer.dall@linaro.org>2013-12-21 10:01:06 -0800
commite1ba0207a1b3714bb3f000e506285ae5123cdfa7 (patch)
treed4a231a1c19b0ae85e391ad43634ee549caf9c34 /virt/kvm
parent39735a3a390431bcf60f9174b7d64f787fd6afa9 (diff)
ARM: KVM: Allow creating the VGIC after VCPUs
Rework the VGIC initialization slightly to allow initialization of the vgic cpu-specific state even if the irqchip (the VGIC) hasn't been created by user space yet. This is safe, because the vgic data structures are already allocated when the CPU is allocated if VGIC support is compiled into the kernel. Further, the init process does not depend on any other information and the sacrifice is a slight performance degradation for creating VMs in the no-VGIC case. The reason is that the new device control API doesn't mandate creating the VGIC before creating the VCPU and it is unreasonable to require user space to create the VGIC before creating the VCPUs. At the same time move the irqchip_in_kernel check out of kvm_vcpu_first_run_init and into the init function to make the per-vcpu and global init functions symmetric and add comments on the exported functions making it a bit easier to understand the init flow by only looking at vgic.c. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'virt/kvm')
1 files changed, 19 insertions, 3 deletions
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 81e9481184a7..5e9df47778fb 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1243,15 +1243,19 @@ static irqreturn_t vgic_maintenance_handler(int irq, void *data)
+ * kvm_vgic_vcpu_init - Initialize per-vcpu VGIC state
+ * @vcpu: pointer to the vcpu struct
+ *
+ * Initialize the vgic_cpu struct and vgic_dist struct fields pertaining to
+ * this vcpu and enable the VGIC for this VCPU
+ */
int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
int i;
- if (!irqchip_in_kernel(vcpu->kvm))
- return 0;
if (vcpu->vcpu_id >= VGIC_MAX_CPUS)
return -EBUSY;
@@ -1383,10 +1387,22 @@ out:
return ret;
+ * kvm_vgic_init - Initialize global VGIC state before running any VCPUs
+ * @kvm: pointer to the kvm struct
+ *
+ * Map the virtual CPU interface into the VM before running any VCPUs. We
+ * can't do this at creation time, because user space must first set the
+ * virtual CPU interface address in the guest physical address space. Also
+ * initialize the ITARGETSRn regs to 0 on the emulated distributor.
+ */
int kvm_vgic_init(struct kvm *kvm)
int ret = 0, i;
+ if (!irqchip_in_kernel(kvm))
+ return 0;
if (vgic_initialized(kvm))