[PATCH 2/9] KVM: arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION read

[Eric Auger]

The doc says:
"The characteristics of a specific redistributor region can
 be read by presetting the index field in the attr data.
 Only valid for KVM_DEV_TYPE_ARM_VGIC_V3"

Unfortunately the existing code fails to read the input attr data
and thus the index always is 0.

Fixes: 04c110932225 ("KVM: arm/arm64: Implement KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION")
Cc: stable@xxxxxxxxxxxxxxx#v4.17+
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index 44419679f91a..2f66cf247282 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -226,6 +226,9 @@ static int vgic_get_common_attr(struct kvm_device *dev,
 		u64 addr;
 		unsigned long type = (unsigned long)attr->attr;
 
+		if (copy_from_user(&addr, uaddr, sizeof(addr)))
+			return -EFAULT;
+
 		r = kvm_vgic_addr(dev->kvm, type, &addr, false);
 		if (r)
 			return (r == -ENODEV) ? -ENXIO : r;
-- 
2.21.3