diff options
| author | Paul Mackerras | 2017-09-13 16:29:22 +1000 |
|---|---|---|
| committer | Paul Mackerras | 2017-10-16 08:09:53 +1100 |
| commit | 891f1ebf659edd24bba93182a8de0ba082dcff72 (patch) | |
| tree | 3515c62ac031ee3ae50ef892e605b7dc6004d087 /arch/powerpc/kvm | |
| parent | 3f2bb76433bb4348cd9076e4d305a040ff2012a9 (diff) | |
KVM: PPC: Book3S HV: Explicitly disable HPT operations on radix guests
This adds code to make sure that we don't try to access the
non-existent HPT for a radix guest using the htab file for the VM
in debugfs, a file descriptor obtained using the KVM_PPC_GET_HTAB_FD
ioctl, or via the KVM_PPC_RESIZE_HPT_{PREPARE,COMMIT} ioctls.
At present nothing bad happens if userspace does access these
interfaces on a radix guest, mostly because kvmppc_hpt_npte()
gives 0 for a radix guest, which in turn is because 1 << -4
comes out as 0 on POWER processors. However, that relies on
undefined behaviour, so it is better to be explicit about not
accessing the HPT for a radix guest.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/kvm')
| -rw-r--r-- | arch/powerpc/kvm/book3s_64_mmu_hv.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 7df89d58ee91..624b01175b79 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -1454,7 +1454,7 @@ long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm, struct kvm_resize_hpt *resize; int ret; - if (flags != 0) + if (flags != 0 || kvm_is_radix(kvm)) return -EINVAL; if (shift && ((shift < 18) || (shift > 46))) @@ -1520,7 +1520,7 @@ long kvm_vm_ioctl_resize_hpt_commit(struct kvm *kvm, struct kvm_resize_hpt *resize; long ret; - if (flags != 0) + if (flags != 0 || kvm_is_radix(kvm)) return -EINVAL; if (shift && ((shift < 18) || (shift > 46))) @@ -1706,6 +1706,8 @@ static ssize_t kvm_htab_read(struct file *file, char __user *buf, if (!access_ok(VERIFY_WRITE, buf, count)) return -EFAULT; + if (kvm_is_radix(kvm)) + return 0; first_pass = ctx->first_pass; flags = ctx->flags; @@ -1803,6 +1805,8 @@ static ssize_t kvm_htab_write(struct file *file, const char __user *buf, if (!access_ok(VERIFY_READ, buf, count)) return -EFAULT; + if (kvm_is_radix(kvm)) + return -EINVAL; /* lock out vcpus from running while we're doing this */ mutex_lock(&kvm->lock); @@ -2001,6 +2005,10 @@ static ssize_t debugfs_htab_read(struct file *file, char __user *buf, struct kvm *kvm; __be64 *hptp; + kvm = p->kvm; + if (kvm_is_radix(kvm)) + return 0; + ret = mutex_lock_interruptible(&p->mutex); if (ret) return ret; @@ -2023,7 +2031,6 @@ static ssize_t debugfs_htab_read(struct file *file, char __user *buf, } } - kvm = p->kvm; i = p->hpt_index; hptp = (__be64 *)(kvm->arch.hpt.virt + (i * HPTE_SIZE)); for (; len != 0 && i < kvmppc_hpt_npte(&kvm->arch.hpt); |