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authorPavel Fedin <p.fedin@samsung.com>2015-12-18 14:38:43 +0300
committerAlex Shi <alex.shi@linaro.org>2016-05-24 22:39:19 +0800
commitf943cd9f551523521a877d0a9aabf415d2746845 (patch)
treea1d5907292c1c17981e7490ad1a2edf604ba14f6
parent7b98d5cccbd0990aed219d388b0b09114d845cfa (diff)
downloadlinux-linaro-stable-f943cd9f551523521a877d0a9aabf415d2746845.tar.gz
arm/arm64: KVM: Detect vGIC presence at runtime
Before commit 662d9715840aef44dcb573b0f9fab9e8319c868a ("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: Pavel Fedin <p.fedin@samsung.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> (cherry picked from commit c7da6fa43cb1c5e649da0f478a491feb9208cae7) Signed-off-by: Alex Shi <alex.shi@linaro.org>
-rw-r--r--arch/arm/kvm/arm.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 60999d8a2cba..529cb22c1251 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -62,6 +62,8 @@ static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
static u8 kvm_next_vmid;
static DEFINE_SPINLOCK(kvm_vmid_lock);
+static bool vgic_present;
+
static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
{
BUG_ON(preemptible());
@@ -132,7 +134,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm->arch.vmid_gen = 0;
/* 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;
out_free_stage2_pgd:
@@ -172,6 +175,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
int r;
switch (ext) {
case KVM_CAP_IRQCHIP:
+ r = vgic_present;
+ break;
case KVM_CAP_IOEVENTFD:
case KVM_CAP_DEVICE_CTRL:
case KVM_CAP_USER_MEMORY:
@@ -860,6 +865,8 @@ static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
switch (dev_id) {
case KVM_ARM_DEVICE_VGIC_V2:
+ if (!vgic_present)
+ return -ENXIO;
return kvm_vgic_addr(kvm, type, &dev_addr->addr, true);
default:
return -ENODEV;
@@ -874,6 +881,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
switch (ioctl) {
case KVM_CREATE_IRQCHIP: {
+ if (!vgic_present)
+ return -ENXIO;
return kvm_vgic_create(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
}
case KVM_ARM_SET_DEVICE_ADDR: {
@@ -1065,8 +1074,17 @@ static int init_hyp_mode(void)
* Init HYP view of VGIC
*/
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;
+ }
/*
* Init HYP architected timer support