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| author | Sean Christopherson <seanjc@google.com> | 2022-01-27 07:31:53 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-01-28 07:32:00 -0500 |
| commit | 56f289a8d23addfa4408a08f07f42fcfe2a7bd69 (patch) | |
| tree | 537c43ada4cd41712fc147053ac6ac178611ee66 /arch/x86/kvm/x86.c | |
| parent | dd4516aee365fc9c944c9d6036b6b87363398680 (diff) | |
| download | lwn-56f289a8d23addfa4408a08f07f42fcfe2a7bd69.tar.gz lwn-56f289a8d23addfa4408a08f07f42fcfe2a7bd69.zip | |
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: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5481d2259f02..76a5dcfcabdb 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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: { |