diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-05-26 14:03:39 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-06-01 14:07:14 -0700 |
| commit | ab322c43cce97ff6d05439c9b72bf1513e3e1020 (patch) | |
| tree | 8a024e2055877fa1e5900250bff12b3680cbd17f /arch/x86/kvm/cpuid.c | |
| parent | 0d42522bdee70b9197be63dd76c9f6297cd1e832 (diff) | |
KVM: x86: Update number of entries for KVM_GET_CPUID2 on success, not failure
Update cpuid->nent if and only if kvm_vcpu_ioctl_get_cpuid2() succeeds.
The sole caller copies @cpuid to userspace only on success, i.e. the
existing code effectively does nothing.
Arguably, KVM should report the number of entries when returning -E2BIG so
that userspace doesn't have to guess the size, but all other similar KVM
ioctls() don't report the size either, i.e. userspace is conditioned to
guess.
Suggested-by: Takahiro Itazuri <itazur@amazon.com>
Link: https://lore.kernel.org/all/20230410141820.57328-1-itazur@amazon.com
Link: https://lore.kernel.org/r/20230526210340.2799158-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 0c9660a07b23..241f554f1764 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -501,20 +501,15 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, struct kvm_cpuid_entry2 __user *entries) { - int r; - - r = -E2BIG; if (cpuid->nent < vcpu->arch.cpuid_nent) - goto out; - r = -EFAULT; + return -E2BIG; + if (copy_to_user(entries, vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2))) - goto out; - return 0; + return -EFAULT; -out: cpuid->nent = vcpu->arch.cpuid_nent; - return r; + return 0; } /* Mask kvm_cpu_caps for @leaf with the raw CPUID capabilities of this CPU. */ |