Commit 56f289a8 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: x86: Add a helper to retrieve userspace address from kvm_device_attr 



Add a helper to handle converting the u64 userspace address embedded in
struct kvm_device_attr into a userspace pointer, it's all too easy to
forget the intermediate "unsigned long" cast as well as the truncation
check.

No functional change intended.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent dd4516ae

arch/x86/kvm/x86.c

+14 −6
Original line number Diff line number Diff line
@@ -4332,7 +4332,15 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) 
		break;

	}

	return r;

}



static inline void __user *kvm_get_attr_addr(struct kvm_device_attr *attr)

{

	void __user *uaddr = (void __user*)(unsigned long)attr->addr;



	if ((u64)(unsigned long)uaddr != attr->addr)

		return ERR_PTR(-EFAULT);

	return uaddr;

}



long kvm_arch_dev_ioctl(struct file *filp,
@@ -5025,11 +5033,11 @@ static int kvm_arch_tsc_has_attr(struct kvm_vcpu *vcpu, 
static int kvm_arch_tsc_get_attr(struct kvm_vcpu *vcpu,

				 struct kvm_device_attr *attr)

{

	u64 __user *uaddr = (u64 __user *)(unsigned long)attr->addr;

	u64 __user *uaddr = kvm_get_attr_addr(attr);

	int r;



	if ((u64)(unsigned long)uaddr != attr->addr)

		return -EFAULT;

	if (IS_ERR(uaddr))

		return PTR_ERR(uaddr);



	switch (attr->attr) {

	case KVM_VCPU_TSC_OFFSET:
@@ -5048,12 +5056,12 @@ static int kvm_arch_tsc_get_attr(struct kvm_vcpu *vcpu, 
static int kvm_arch_tsc_set_attr(struct kvm_vcpu *vcpu,

				 struct kvm_device_attr *attr)

{

	u64 __user *uaddr = (u64 __user *)(unsigned long)attr->addr;

	u64 __user *uaddr = kvm_get_attr_addr(attr);

	struct kvm *kvm = vcpu->kvm;

	int r;



	if ((u64)(unsigned long)uaddr != attr->addr)

		return -EFAULT;

	if (IS_ERR(uaddr))

		return PTR_ERR(uaddr);



	switch (attr->attr) {

	case KVM_VCPU_TSC_OFFSET: {