KVM: arm/arm64: vgic-new: vgic_kvm_device: access to VGIC registers

This patch implements the switches for KVM_DEV_ARM_VGIC_GRP_DIST_REGS
and KVM_DEV_ARM_VGIC_GRP_CPU_REGS API which allows the userspace to
access VGIC registers.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index a7090970be7237447c01c0a9b3c38927cc049ec2..78621283a3014667a2fc1ec6cb1bc15910925707 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -226,6 +226,21 @@ void kvm_register_vgic_device(unsigned long type)
        }
 }
 
+/** vgic_attr_regs_access: allows user space to read/write VGIC registers
+ *
+ * @dev: kvm device handle
+ * @attr: kvm device attribute
+ * @reg: address the value is read or written
+ * @is_write: write flag
+ *
+ */
+static int vgic_attr_regs_access(struct kvm_device *dev,
+                                struct kvm_device_attr *attr,
+                                u32 *reg, bool is_write)
+{
+       return -ENXIO;
+}
+
 /* V2 ops */
 
 static int vgic_v2_set_attr(struct kvm_device *dev,
@@ -234,8 +249,23 @@ static int vgic_v2_set_attr(struct kvm_device *dev,
        int ret;
 
        ret = vgic_set_common_attr(dev, attr);
-       return ret;
+       if (ret != -ENXIO)
+               return ret;
+
+       switch (attr->group) {
+       case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
+       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
+               u32 __user *uaddr = (u32 __user *)(long)attr->addr;
+               u32 reg;
+
+               if (get_user(reg, uaddr))
+                       return -EFAULT;
 
+               return vgic_attr_regs_access(dev, attr, &reg, true);
+       }
+       }
+
+       return -ENXIO;
 }
 
 static int vgic_v2_get_attr(struct kvm_device *dev,
@@ -244,7 +274,23 @@ static int vgic_v2_get_attr(struct kvm_device *dev,
        int ret;
 
        ret = vgic_get_common_attr(dev, attr);
-       return ret;
+       if (ret != -ENXIO)
+               return ret;
+
+       switch (attr->group) {
+       case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
+       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS: {
+               u32 __user *uaddr = (u32 __user *)(long)attr->addr;
+               u32 reg = 0;
+
+               ret = vgic_attr_regs_access(dev, attr, &reg, false);
+               if (ret)
+                       return ret;
+               return put_user(reg, uaddr);
+       }
+       }
+
+       return -ENXIO;
 }
 
 static int vgic_v2_has_attr(struct kvm_device *dev,
@@ -258,6 +304,9 @@ static int vgic_v2_has_attr(struct kvm_device *dev,
                        return 0;
                }
                break;
+       case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
+       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
+               return vgic_v2_has_attr_regs(dev, attr);
        case KVM_DEV_ARM_VGIC_GRP_NR_IRQS:
                return 0;
        case KVM_DEV_ARM_VGIC_GRP_CTRL:

diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index 3925d4cbec62a2332268bad243da1332252b0f10..71896900ad1217d8b86009a8f78ed459ad9d7925 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -258,3 +258,41 @@ unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev)
 
        return SZ_4K;
 }
+
+int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
+{
+       int nr_irqs = dev->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
+       const struct vgic_register_region *regions;
+       gpa_t addr;
+       int nr_regions, i, len;
+
+       addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
+
+       switch (attr->group) {
+       case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
+               regions = vgic_v2_dist_registers;
+               nr_regions = ARRAY_SIZE(vgic_v2_dist_registers);
+               break;
+       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
+               return -ENXIO;          /* TODO: describe CPU i/f regs also */
+       default:
+               return -ENXIO;
+       }
+
+       /* We only support aligned 32-bit accesses. */
+       if (addr & 3)
+               return -ENXIO;
+
+       for (i = 0; i < nr_regions; i++) {
+               if (regions[i].bits_per_irq)
+                       len = (regions[i].bits_per_irq * nr_irqs) / 8;
+               else
+                       len = regions[i].len;
+
+               if (regions[i].reg_offset <= addr &&
+                   regions[i].reg_offset + len > addr)
+                       return 0;
+       }
+
+       return -ENXIO;
+}

diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 6abc9a35c228526eafa99695531c0515a80b1335..a264c5ff476e7bc759217632a4c15dc51820e20f 100644 (file)
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -37,6 +37,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu);
 void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr);
 void vgic_v2_clear_lr(struct kvm_vcpu *vcpu, int lr);
 void vgic_v2_set_underflow(struct kvm_vcpu *vcpu);
+int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr);
 int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
                             enum vgic_type);