[PATCH v4 46/56] KVM: arm/arm64: vgic-new: Add userland access to VGIC dist registers
From: Christoffer Dall <hidden>
Date: 2016-05-18 13:57:24
Also in:
kvm, kvmarm
On Mon, May 16, 2016 at 10:53:34AM +0100, Andre Przywara wrote:
quoted hunk ↗ jump to hunk
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@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(). + */
We still have a problem here. Want me to write a patch? -Christoffer
+ 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