Commit c7da6fa4 authored by Pavel Fedin's avatar Pavel Fedin Committed by Marc Zyngier

arm/arm64: KVM: Detect vGIC presence at runtime

Before commit 662d9715
("arm/arm64: KVM: Kill CONFIG_KVM_ARM_{VGIC,TIMER}") is was possible to
compile the kernel without vGIC and vTimer support. Commit message says
about possibility to detect vGIC support in runtime, but this has never
been implemented.

This patch introduces runtime check, restoring the lost functionality.
It again allows to use KVM on hardware without vGIC. Interrupt
controller has to be emulated in userspace in this case.

-ENODEV return code from probe function means there's no GIC at all.
-ENXIO happens when, for example, there is GIC node in the device tree,
but it does not specify vGIC resources. Any other error code is still
treated as full stop because it might mean some really serious problems.
Signed-off-by: default avatarPavel Fedin <p.fedin@samsung.com>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 1b1ebe82
...@@ -63,6 +63,8 @@ static u32 kvm_next_vmid; ...@@ -63,6 +63,8 @@ static u32 kvm_next_vmid;
static unsigned int kvm_vmid_bits __read_mostly; static unsigned int kvm_vmid_bits __read_mostly;
static DEFINE_SPINLOCK(kvm_vmid_lock); static DEFINE_SPINLOCK(kvm_vmid_lock);
static bool vgic_present;
static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu) static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
{ {
BUG_ON(preemptible()); BUG_ON(preemptible());
...@@ -134,7 +136,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) ...@@ -134,7 +136,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm->arch.vmid_gen = 0; kvm->arch.vmid_gen = 0;
/* The maximum number of VCPUs is limited by the host's GIC model */ /* The maximum number of VCPUs is limited by the host's GIC model */
kvm->arch.max_vcpus = kvm_vgic_get_max_vcpus(); kvm->arch.max_vcpus = vgic_present ?
kvm_vgic_get_max_vcpus() : KVM_MAX_VCPUS;
return ret; return ret;
out_free_stage2_pgd: out_free_stage2_pgd:
...@@ -174,6 +177,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) ...@@ -174,6 +177,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
int r; int r;
switch (ext) { switch (ext) {
case KVM_CAP_IRQCHIP: case KVM_CAP_IRQCHIP:
r = vgic_present;
break;
case KVM_CAP_IOEVENTFD: case KVM_CAP_IOEVENTFD:
case KVM_CAP_DEVICE_CTRL: case KVM_CAP_DEVICE_CTRL:
case KVM_CAP_USER_MEMORY: case KVM_CAP_USER_MEMORY:
...@@ -917,6 +922,8 @@ static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm, ...@@ -917,6 +922,8 @@ static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
switch (dev_id) { switch (dev_id) {
case KVM_ARM_DEVICE_VGIC_V2: case KVM_ARM_DEVICE_VGIC_V2:
if (!vgic_present)
return -ENXIO;
return kvm_vgic_addr(kvm, type, &dev_addr->addr, true); return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
default: default:
return -ENODEV; return -ENODEV;
...@@ -931,6 +938,8 @@ long kvm_arch_vm_ioctl(struct file *filp, ...@@ -931,6 +938,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
switch (ioctl) { switch (ioctl) {
case KVM_CREATE_IRQCHIP: { case KVM_CREATE_IRQCHIP: {
if (!vgic_present)
return -ENXIO;
return kvm_vgic_create(kvm, KVM_DEV_TYPE_ARM_VGIC_V2); return kvm_vgic_create(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
} }
case KVM_ARM_SET_DEVICE_ADDR: { case KVM_ARM_SET_DEVICE_ADDR: {
...@@ -1121,8 +1130,17 @@ static int init_hyp_mode(void) ...@@ -1121,8 +1130,17 @@ static int init_hyp_mode(void)
* Init HYP view of VGIC * Init HYP view of VGIC
*/ */
err = kvm_vgic_hyp_init(); err = kvm_vgic_hyp_init();
if (err) switch (err) {
case 0:
vgic_present = true;
break;
case -ENODEV:
case -ENXIO:
vgic_present = false;
break;
default:
goto out_free_context; goto out_free_context;
}
/* /*
* Init HYP architected timer support * Init HYP architected timer support
......
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