KVM: arm64: vgic-v2: Consolidate userspace access for MMIO registers

Align the GICv2 MMIO accesses from userspace with the way the GICv3
code is now structured.

Reviewed-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index e9db679..066b95d 100644 (file)
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -348,17 +348,18 @@ bool lock_all_vcpus(struct kvm *kvm)
  *
  * @dev:      kvm device handle
  * @attr:     kvm device attribute
- * @reg:      address the value is read or written
  * @is_write: true if userspace is writing a register
  */
 static int vgic_v2_attr_regs_access(struct kvm_device *dev,
                                    struct kvm_device_attr *attr,
-                                   u32 *reg, bool is_write)
+                                   bool is_write)
 {
+       u32 __user *uaddr = (u32 __user *)(unsigned long)attr->addr;
        struct vgic_reg_attr reg_attr;
        gpa_t addr;
        struct kvm_vcpu *vcpu;
        int ret;
+       u32 val;
 
        ret = vgic_v2_parse_attr(dev, attr, &reg_attr);
        if (ret)
@@ -367,6 +368,10 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
        vcpu = reg_attr.vcpu;
        addr = reg_attr.addr;
 
+       if (is_write)
+               if (get_user(val, uaddr))
+                       return -EFAULT;
+
        mutex_lock(&dev->kvm->lock);
 
        ret = vgic_init(dev->kvm);
@@ -380,10 +385,10 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
 
        switch (attr->group) {
        case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
-               ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, reg);
+               ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, &val);
                break;
        case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
-               ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, reg);
+               ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, &val);
                break;
        default:
                ret = -EINVAL;
@@ -393,6 +398,10 @@ static int vgic_v2_attr_regs_access(struct kvm_device *dev,
        unlock_all_vcpus(dev->kvm);
 out:
        mutex_unlock(&dev->kvm->lock);
+
+       if (!ret && !is_write)
+               ret = put_user(val, uaddr);
+
        return ret;
 }
 
@@ -407,15 +416,8 @@ static int vgic_v2_set_attr(struct kvm_device *dev,
 
        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_v2_attr_regs_access(dev, attr, &reg, true);
-       }
+       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
+               return vgic_v2_attr_regs_access(dev, attr, true);
        }
 
        return -ENXIO;
@@ -432,15 +434,8 @@ static int vgic_v2_get_attr(struct kvm_device *dev,
 
        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_v2_attr_regs_access(dev, attr, &reg, false);
-               if (ret)
-                       return ret;
-               return put_user(reg, uaddr);
-       }
+       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
+               return vgic_v2_attr_regs_access(dev, attr, false);
        }
 
        return -ENXIO;