[PATCH v4 46/56] KVM: arm/arm64: vgic-new: Add userland access to VGIC dist registers
Andre Przywara
andre.przywara at arm.com
Mon May 16 02:53:34 PDT 2016
Userland may want to save and restore the state of the in-kernel VGIC,
so we provide the code which takes a userland request and translate
that into calls to our MMIO framework.
Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
virt/kvm/arm/vgic/vgic-kvm-device.c | 50 ++++++++++++++++++++++++++++++++++++-
1 file changed, 49 insertions(+), 1 deletion(-)
diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index 78621283..c3ec453 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -238,7 +238,55 @@ static int vgic_attr_regs_access(struct kvm_device *dev,
struct kvm_device_attr *attr,
u32 *reg, bool is_write)
{
- return -ENXIO;
+ gpa_t addr;
+ int cpuid, ret, c;
+ struct kvm_vcpu *vcpu, *tmp_vcpu;
+
+ cpuid = (attr->attr & KVM_DEV_ARM_VGIC_CPUID_MASK) >>
+ KVM_DEV_ARM_VGIC_CPUID_SHIFT;
+ vcpu = kvm_get_vcpu(dev->kvm, cpuid);
+ addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
+
+ mutex_lock(&dev->kvm->lock);
+
+ ret = vgic_init(dev->kvm);
+ if (ret)
+ goto out;
+
+ if (cpuid >= atomic_read(&dev->kvm->online_vcpus)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Ensure that no other VCPU is running by checking the vcpu->cpu
+ * field. If no other VPCUs are running we can safely access the VGIC
+ * state, because even if another VPU is run after this point, that
+ * VCPU will not touch the vgic state, because it will block on
+ * getting the vgic->lock in kvm_vgic_sync_hwstate().
+ */
+ kvm_for_each_vcpu(c, tmp_vcpu, dev->kvm) {
+ if (unlikely(tmp_vcpu->cpu != -1)) {
+ ret = -EBUSY;
+ goto out;
+ }
+ }
+
+ switch (attr->group) {
+ case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
+ ret = -EINVAL;
+ break;
+ case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
+ ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, reg);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+out:
+ mutex_unlock(&dev->kvm->lock);
+ return ret;
}
/* V2 ops */
--
2.8.2
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